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Sample records for ce entrained fuel process

  1. Entrainment.

    ERIC Educational Resources Information Center

    Carrier, Romance F.

    1978-01-01

    Presents a literature review including: (1) theoretical studies concerned with the development of methdology to determine the significance of entrainment effects to whale populations and ecosystems; and (2) site and laboratory studies. A list of 107 references drawn from the 1976 and 1977 literature is also presented. (HM)

  2. MODELING AND DESIGN FOR A DIRECT CARBON FUEL CELL WITH ENTRAINED FUEL AND OXIDIZER

    SciTech Connect

    Alan A. Kornhauser; Ritesh Agarwal

    2005-04-01

    The novel molten carbonate fuel cell design described in this report uses porous bed electrodes. Molten carbonate, with carbon fuel particles and oxidizer entrained, is circulated through the electrodes. Carbon may be reacted directly, without gasification, in a molten carbonate fuel cell. The cathode reaction is 2CO{sub 2} + O{sub 2} 4e{sup -} {yields} 2CO{sub 3}{sup =}, while the anode reaction can be either C + 2CO{sub 3}{sup =} {yields} 3CO{sub 2} + 4e{sup -} or 2C + CO{sub 3}{sup =} {yields} 3CO + 2e{sup -}. The direct carbon fuel cell has an advantage over fuel cells using coal-derived synthesis gas in that it provides better overall efficiency and reduces equipment requirements. Also, the liquid electrolyte provides a means for transporting the solid carbon. The porous bed cell makes use of this carbon transport ability of the molten salt electrolyte. A one-dimensional model has been developed for predicting the performance of this cell. For the cathode, dependent variables are superficial O{sub 2} and CO{sub 2} fluxes in the gas phase, superficial O{sub 2} and CO{sub 2} fluxes in the liquid phase, superficial current density through the electrolyte, and electrolyte potential. The variables are related by correlations, from the literature, for gas-liquid mass transfer, liquid-solid mass transfer, cathode current density, electrode overpotential, and resistivity of a liquid with entrained gas. For the anode, dependent variables are superficial CO{sub 2} flux in the gas phase, superficial CO{sub 2} flux in the liquid phase, superficial C flux, superficial current density through the electrolyte, and electrolyte potential. The same types of correlations relate the variables as in the cathode, with the addition of a correlation for resistivity of a fluidized bed. CO production is not considered, and axial dispersion is neglected. The model shows behavior typical of porous bed electrodes used in electrochemical processes. Efficiency is comparable to that of

  3. Problems with the process partitioning theory of stratocumulus entrainment

    NASA Technical Reports Server (NTRS)

    Randall, D. A.

    1984-01-01

    Three different approaches to partitioning were proposed. Ball (1960), Lilly (1968), and Deardorff et al. (1969, 1974) considered the sign of the net buoyancy flux at each level. If the net flux is positive, it is counted as TKE producing; otherwise, it is counted as TKE consuming. This approach can be called Eulerian partitioning. The second approach can be called process partitioning. It is assumed that the various processes acting in concert each produce and consume the same energy as if they acted independently (Manins and Turner, 1978). The total rates of TKE production and consumption are obtained by summing the effects of all the forcing processes. The third approach is Lagrangian partitioning. Each air parcel is considered as either producing or consuming TKE, according to the sign of the product of its density and vertical velocity anomalies. Stage and Businger (1981a,b) have applied process partitioning to the cloud topped mixed layer. One of the most important processes influencing entrainment into such a layer is cloud top radiative cooling. The production and consumption due to entrainment and radiative cooling are thus closely related. Model results are sensitive to the choice of formulation.

  4. The Macroscopic Entrainment Processes of Simulated Cumulus Ensemble. Part II: Testing the Entraining-Plume Model.

    NASA Astrophysics Data System (ADS)

    Lin, Chichung; Arakawa, Akio

    1997-04-01

    According to Part I of this paper, it seems that ignoring the contribution from descendent cloud air in a cloud model for cumulus parameterization (CMCP), such as the spectral cumulus ensemble model in the Arakawa-Schubert parameterization, is an acceptable simplification for tropical deep convection. Since each subensemble in the spectral cumulus ensemble model is formally analogous to an entraining plume, the latter is examined using the simulated data from a cloud-resolving model (CRM). The authors first follow the analysis procedure of Warner. With the data from a nonprecipitating experiment, the authors show that the entraining-plume model cannot simultaneously predict the mean liquid water profile and cloud top height of the clouds simulated by the CRM. However, the mean properties of active elements of clouds, which are characterized by strong updrafts, can be described by an entraining plume of similar top height.With the data from a precipitating experiment, the authors examine the spectral cumulus ensemble model using the Paluch diagram. It is found that the spectral cumulus ensemble model appears adequate if different types of clouds in the spectrum are interpreted as subcloud elements with different entrainment characteristics. The resolved internal structure of clouds can thus be viewed as a manifestation of a cloud spectrum. To further investigate whether the fractional rate of entrainment is an appropriate parameter for characterizing cloud types in the spectral cumulus ensemble model, the authors stratify the simulated saturated updrafts (subcloud elements) into different types according to their eventual heights and calculate the cloud mass flux and mean moist static energy for each type. Entrainment characteristics are then inferred through the cloud mass flux and in-cloud moist static energy. It is found that different types of subcloud elements have distinguishable thermodynamic properties and entrainment characteristics. However, for each cloud

  5. Entrainment and mixing processes in downslope gravity currents.

    NASA Astrophysics Data System (ADS)

    Shishova, Anna; Gritsenko, Vladimir

    2010-05-01

    Downslope density currents play a significant role in vertical water exchange in near-shore zones of lakes, seas and oceans. Entrainment and mixing processes at the density currents' interface has been described by many authors (e.g., Barenblatt, Benjamin, Britter & Linden, Simpson, Turner, Holyer & Huppert, Baines), however further understanding is still required. Main objective of the present work is the analysis of mixing processes, associated with density current propagating along the bottom, based on examination of simulated flows. The simulations were carried out by using a non-linear two-dimensional XZ-model, which solves the following system of equations: D?/Dt = (g/ρ0) (δσ/δz) + νT??; ?φ = ?; Dρ/Dt = kT?ρ; Dc/Dt = kT?c, where ? - is the flow vorticity, φ - stream function, g=982 cm/s2, ρ0=1 g/cm3 - fresh water density, ρ - saline water density, x, z - horizontal and vertical coordinates, respectively; t - time; D/Dt = δ/δt + uδ/δx + wδ/δz; ? = δ2/δx2 + δ2/δz2; νT = ν0 + c×νeff, kT = 0.5νT - turbulent diffusivity and viscosity coefficients, νeff = √Re×ν 0; Re = u0×h0/ν0; ν0 = 0.015 cm2/s; ν eff = 0 at t=0; c=c(x, z, t), 0.0≤c≤1.0 - dimensionless concentration of tracer of the bottom current water mass. For description and comprehension of specific features of mixing processes in downslope currents the approach suggested by Baines (J. Fluid Mech. 2001, vol. 443) is used, based upon employing local parameters and local averaging. Following Baines, four dimensionless parameters were chosen for the description of the basic flow: slope angle ?, Richardson number Ri = g'd3cosq/Q2, Reynolds number Re = Q/ν and M = Q/(g'D3)0,5= QN3/g'2 - the ambient fluid stratification coefficient; here, ν - kinematical viscosity, d - average thickness of the downflow. Two important additional parameters were defined: N - buoyancy frequency, and an associated parameter D - the depth below the source where the initial density of the fluid in

  6. Process for coal liquefaction by separation of entrained gases from slurry exiting staged dissolvers

    DOEpatents

    Givens, Edwin N.; Ying, David H. S.

    1983-01-01

    There is described an improved liquefaction process by which coal is converted to a low ash and low sulfur carbonaceous material that can be used as a fuel in an environmentally acceptable manner without costly gas scrubbing equipment. In the process, coal is slurried with a solvent, passed through a preheater and at least two dissolvers in series in the presence of hydrogen-rich gases at elevated temperatures and pressures. Solids, including mineral ash and unconverted coal macerals are separated from the condensed dissolver effluent. In accordance with the improved process, fresh hydrogen is fed to each dissolver and the entrained gas from each dissolver is separated from the slurry phase and removed from the reactor system before the condensed phase is passed to the next dissolver in the series. In accordance with another process, the feeds to the dissolvers are such that the top of each downstream dissolver is used as a gas-liquid separator.

  7. Development of an entrained flow gasifier model for process optimization study

    SciTech Connect

    Biagini, E.; Bardi, A.; Pannocchia, G.; Tognotti, L.

    2009-10-15

    Coal gasification is a versatile process to convert a solid fuel in syngas, which can be further converted and separated in hydrogen, which is a valuable and environmentally acceptable energy carrier. Different technologies (fixed beds, fluidized beds, entrained flow reactors) are used, operating under different conditions of temperature, pressure, and residence time. Process studies should be performed for defining the best plant configurations and operating conditions. Although 'gasification models' can be found in the literature simulating equilibrium reactors, a more detailed approach is required for process analysis and optimization procedures. In this work, a gasifier model is developed by using AspenPlus as a tool to be implemented in a comprehensive process model for the production of hydrogen via coal gasification. It is developed as a multizonal model by interconnecting each step of gasification (preheating, devolatilization, combustion, gasification, quench) according to the reactor configuration, that is in entrained flow reactor. The model removes the hypothesis of equilibrium by introducing the kinetics of all steps and solves the heat balance by relating the gasification temperature to the operating conditions. The model allows to predict the syngas composition as well as quantity the heat recovery (for calculating the plant efficiency), 'byproducts', and residual char. Finally, in view of future works, the development of a 'gasifier model' instead of a 'gasification model' will allow different reactor configurations to be compared.

  8. The Role of High-Level Processes for Oscillatory Phase Entrainment to Speech Sound.

    PubMed

    Zoefel, Benedikt; VanRullen, Rufin

    2015-01-01

    Constantly bombarded with input, the brain has the need to filter out relevant information while ignoring the irrelevant rest. A powerful tool may be represented by neural oscillations which entrain their high-excitability phase to important input while their low-excitability phase attenuates irrelevant information. Indeed, the alignment between brain oscillations and speech improves intelligibility and helps dissociating speakers during a "cocktail party". Although well-investigated, the contribution of low- and high-level processes to phase entrainment to speech sound has only recently begun to be understood. Here, we review those findings, and concentrate on three main results: (1) Phase entrainment to speech sound is modulated by attention or predictions, likely supported by top-down signals and indicating higher-level processes involved in the brain's adjustment to speech. (2) As phase entrainment to speech can be observed without systematic fluctuations in sound amplitude or spectral content, it does not only reflect a passive steady-state "ringing" of the cochlea, but entails a higher-level process. (3) The role of intelligibility for phase entrainment is debated. Recent results suggest that intelligibility modulates the behavioral consequences of entrainment, rather than directly affecting the strength of entrainment in auditory regions. We conclude that phase entrainment to speech reflects a sophisticated mechanism: several high-level processes interact to optimally align neural oscillations with predicted events of high relevance, even when they are hidden in a continuous stream of background noise. PMID:26696863

  9. The Role of High-Level Processes for Oscillatory Phase Entrainment to Speech Sound

    PubMed Central

    Zoefel, Benedikt; VanRullen, Rufin

    2015-01-01

    Constantly bombarded with input, the brain has the need to filter out relevant information while ignoring the irrelevant rest. A powerful tool may be represented by neural oscillations which entrain their high-excitability phase to important input while their low-excitability phase attenuates irrelevant information. Indeed, the alignment between brain oscillations and speech improves intelligibility and helps dissociating speakers during a “cocktail party”. Although well-investigated, the contribution of low- and high-level processes to phase entrainment to speech sound has only recently begun to be understood. Here, we review those findings, and concentrate on three main results: (1) Phase entrainment to speech sound is modulated by attention or predictions, likely supported by top-down signals and indicating higher-level processes involved in the brain’s adjustment to speech. (2) As phase entrainment to speech can be observed without systematic fluctuations in sound amplitude or spectral content, it does not only reflect a passive steady-state “ringing” of the cochlea, but entails a higher-level process. (3) The role of intelligibility for phase entrainment is debated. Recent results suggest that intelligibility modulates the behavioral consequences of entrainment, rather than directly affecting the strength of entrainment in auditory regions. We conclude that phase entrainment to speech reflects a sophisticated mechanism: several high-level processes interact to optimally align neural oscillations with predicted events of high relevance, even when they are hidden in a continuous stream of background noise. PMID:26696863

  10. Research on the pyrolysis of hardwood in an entrained bed process development unit

    SciTech Connect

    Kovac, R.J.; Gorton, C.W.; Knight, J.A.; Newman, C.J.; O'Neil, D.J. . Research Inst.)

    1991-08-01

    An atmospheric flash pyrolysis process, the Georgia Tech Entrained Flow Pyrolysis Process, for the production of liquid biofuels from oak hardwood is described. The development of the process began with bench-scale studies and a conceptual design in the 1978--1981 timeframe. Its development and successful demonstration through research on the pyrolysis of hardwood in an entrained bed process development unit (PDU), in the period of 1982--1989, is presented. Oil yields (dry basis) up to 60% were achieved in the 1.5 ton-per-day PDU, far exceeding the initial target/forecast of 40% oil yields. Experimental data, based on over forty runs under steady-state conditions, supported by material and energy balances of near-100% closures, have been used to establish a process model which indicates that oil yields well in excess of 60% (dry basis) can be achieved in a commercial reactor. Experimental results demonstrate a gross product thermal efficiency of 94% and a net product thermal efficiency of 72% or more; the highest values yet achieved with a large-scale biomass liquefaction process. A conceptual manufacturing process and an economic analysis for liquid biofuel production at 60% oil yield from a 200-TPD commercial plant is reported. The plant appears to be profitable at contemporary fuel costs of $21/barrel oil-equivalent. Total capital investment is estimated at under $2.5 million. A rate-of-return on investment of 39.4% and a pay-out period of 2.1 years has been estimated. The manufacturing cost of the combustible pyrolysis oil is $2.70 per gigajoule. 20 figs., 87 tabs.

  11. Flame deformation and entrainment associated with an isothermal transverse fuel jet

    NASA Technical Reports Server (NTRS)

    Jenkins, D. W.; Karagozian, A. R.

    1992-01-01

    This paper describes an analytical model of an incompressible, isothermal reacting jet in crossflow. The model represents the flow in the jet cross-section by a counter rotating vortex pair, a flow structure that has been observed to dominate the jet behavior. The reaction surface surrounding the fuel jet is represented as a composite of strained diffusion flames that are stretched and deformed by the vortex pair flow. The results shed new light on the interaction between the vortex pair circulation and flame structure evolution and their relation to the concept of entrainment.

  12. Foaming and Antifoaming and Gas Entrainment in Radioactive Waste Preteatment and Immobilization Processes

    SciTech Connect

    Wasan, Darsh T.; Nikolov, Alex

    2005-06-01

    The objectives of this research effort are to develop a fundamental understanding of the physico-chemical mechanisms that produce foaming and air entrainment in the DOE High Level (HLW) and Low Activity (LAW) radioactive waste separation and immobilization processes, and to develop and test advanced antifoam/defoaming/rheology modifier agents. Antifoams/rheology modifiers developed from this research will be tested using non-radioactive simulants of the radioactive wastes obtained from Hanford and the Savannah River Site (SRS).

  13. ENTRAINMENT MODELS

    EPA Science Inventory

    This presentation presented information on entrainment models. Entrainment models use entrainment hypotheses to express the continuity equation. The advantage is that plume boundaries are known. A major disadvantage is that the problems that can be solved are rather simple. The ...

  14. Entrainment process at the base of the upper ocean layer in an upwelling filament area

    NASA Astrophysics Data System (ADS)

    Estrada-Allis, Sheila; Rodríguez-Santana, Ángel

    2014-05-01

    Entrainment is responsible for the deepening of the mixed layer and controls the transport of momentum, heat, salinity and nutrients across the interface between the turbulent mixed layer and non-turbulent layer below. This process, which is not yet well understood, can be mechanically forced by wind stirring and buoyancy forced through vertical heat fluxes. In strongly dynamical areas such as eastern boundary upwelling systems and their associated filaments, entrainment rates can also be influenced by vertical shear at the base of the mixed layer that may results from advected baroclinic instabilities. We investigate these processes in the Northwest African upwelling region and Cape Ghir filament using CTD, XBT, ADCP, a meteorological station on board for the wind data and heat flux measurements taken during October 2010, as well as one of the first microturbulent profile (TurboMAP) measurements taken in this area in order to obtain the TKE dissipation rate. We find that buoyancy production dominates over the wind induced mixing in the mixed layer of this region as indicate the Monin Obukhov length scale. To determine entrainment rates we compare four parameterizations based on the turbulent kinetic energy (TKE) balance and one based on the relation of the bulk Richardson number. Although there is no clear consensus between these four parameterizations, they provide evidence that vertical shear at the base of the mixed layer acts to enhance the entrainment rate, especially at stations effected by the upwelling filament or mesoscalar structures. We further compare the measured TKE dissipation rates to those parameterized of Gaspar (1988) and Deardorff (1983). Moreover, some relevant aspect relative to the study of turbulent process in the upper ocean layer, such as the choice of an algorithm or criteria to find the mixed layer depth and the difference between mixing and mixed layer are addressed. This work was funded by Spanish Government (PROMECA: CTM2008

  15. Exploring Stratocumulus Cloud-Top Entrainment Processes and Parameterizations Using Doppler Cloud Radar Observations

    NASA Astrophysics Data System (ADS)

    Albrecht, B. A.; Fang, M.

    2012-12-01

    define vertical velocity variance for one-hour periods. These quantities are then used to examine the terms in the TKE budget in this layer. It is found for the 14 hours of observations used in this study that the variance term is strongly correlated to the dissipation rates in the entrainment zone. However, the ratio of the variance term to the dissipation rate term is 0.12 during the day and 0.06 at night. This difference indicates that the length scales involved in the turbulence and entrainment processes may depend on whether the turbulence is forced by the surface fluxes or cloud-top cooling. To further explore this possibility, the relationships among the convective velocity scales, the vertical velocity variances, and the dissipation rates are examined and compared with entrainment rates from parameterizations based on the convective velocity scale and the strength of the inversion.

  16. Subtask 3.16 - Low-Cost Coal-Water Fuel for Entrained-Flow Gasification

    SciTech Connect

    Anderson, C.M.

    1997-10-01

    The specific objective of this research project is to assess the potential process efficiency and pollution control benefits that may occur by applying the hydrothermal, or hot water-drying, process to low-rank coals as related to entrained-flow gasification systems. Project emphasis is on identifying more efficient coal dewatering and CWF formulation methods prior to gasification. A favorable estimate of incremental cost for integrated hydrothermal drying depends, in part, on increasing the particle size of the feed coal from minus 100 to minus 28 mesh for the purpose of simplifying the slurry concentration process. Two options will be reviewed for dewatering or concentrating the processed slurry: (1) repressurization and then concentration with sieve bends or (2) partial dewatering at system pressure with hydroclones. Both have their own merits, sieve bends being a low-cost alternative, while hydroclone application would not require additional pumping sections prior to gasification. Various CWF samples with different particle-size distributions and solids concentrations will be sent to equipment vendors for application review. Also, EERC cost models will be used to calculate the integral cost of adding the partial dewatering to the hydrothermal technology for a commercial-size facility.

  17. A time-variant processing approach for the analysis of alpha and gamma MEG oscillations during flicker stimulus generated entrainment.

    PubMed

    Wacker, Matthias; Galicki, Miroslav; Putsche, Peter; Milde, Thomas; Schwab, Karin; Haueisen, Jens; Ligges, Carolin; Witte, Herbert

    2011-11-01

    Repetitive flicker stimulation (photic driving) offers the possibility to study the properties and coupling characteristics of stimulation-sensitive neuronal oscillators by means of the MEG/EEG analysis. With flicker frequencies in the region of the individual alpha band frequency, the dynamics of the entrainment process of the alpha oscillation, as well as the dynamics of the accompanying gamma oscillations and the coupling between the oscillations, are investigated by means of an appropriate combination of time-variant analysis methods. The Hilbert and the Gabor transformation reveal time-variant properties (frequency entrainment, phase locking, and n:m synchronization) of the entrainment process in the whole frequency range. Additionally, time-variant partial directed coherence is applied to identify ocular saccadic interferences and to study the directed information transfer between the recording sites of the simultaneously derived MEG/EEG data during the entrainment. The MEG data is the focus of this methodological study as the entrainment effects of the alpha oscillation are stronger in MEG than in the EEG. The occipital brain region (visual cortex) was mainly investigated and the dynamics of the alpha entrainment quantified. It can be shown that at the beginning of this entrainment, a transient, strongly phase-locked "40-Hz" gamma oscillation occurs. PMID:21712153

  18. Final Report - "Foaming and Antifoaming and Gas Entrainment in Radioactive Waste Pretreatment and Immobilization Processes"

    SciTech Connect

    Wasan, Darsh T.

    2007-10-09

    The Savannah River Site (SRS) and Hanford site are in the process of stabilizing millions of gallons of radioactive waste slurries remaining from production of nuclear materials for the Department of Energy (DOE). The Defense Waste Processing Facility (DWPF) at SRS is currently vitrifying the waste in borosilicate glass, while the facilities at the Hanford site are in the construction phase. Both processes utilize slurry-fed joule-heated melters to vitrify the waste slurries. The DWPF has experienced difficulty during operations. The cause of the operational problems has been attributed to foaming, gas entrainment and the rheological properties of the process slurries. The rheological properties of the waste slurries limit the total solids content that can be processed by the remote equipment during the pretreatment and meter feed processes. Highly viscous material can lead to air entrainment during agitation and difficulties with pump operations. Excessive foaming in waste evaporators can cause carryover of radionuclides and non-radioactive waste to the condensate system. Experimental and theoretical investigations of the surface phenomena, suspension rheology and bubble generation of interactions that lead to foaming and air entrainment problems in the DOE High Level and Low Activity Radioactive Waste separation and immobilization processes were pursued under this project. The first major task accomplished in the grant proposal involved development of a theoretical model of the phenomenon of foaming in a three-phase gas-liquid-solid slurry system. This work was presented in a recently completed Ph.D. thesis (9). The second major task involved the investigation of the inter-particle interaction and microstructure formation in a model slurry by the batch sedimentation method. Both experiments and modeling studies were carried out. The results were presented in a recently completed Ph.D. thesis. The third task involved the use of laser confocal microscopy to study

  19. Fuel gas conditioning process

    DOEpatents

    Lokhandwala, Kaaeid A.

    2000-01-01

    A process for conditioning natural gas containing C.sub.3+ hydrocarbons and/or acid gas, so that it can be used as combustion fuel to run gas-powered equipment, including compressors, in the gas field or the gas processing plant. Compared with prior art processes, the invention creates lesser quantities of low-pressure gas per unit volume of fuel gas produced. Optionally, the process can also produce an NGL product.

  20. Observing Entrainment Processes Using a Small Unmanned Aerial Vehicle: A Feasibility Study

    NASA Astrophysics Data System (ADS)

    Martin, Sabrina; Beyrich, Frank; Bange, Jens

    2014-03-01

    Measurement flights with the meteorological mini aerial vehicle (MAV) were performed in spring 2011 to assess the capability of an unmanned aerial vehicle (UAV) to measure the structure of the transition zone between the convective boundary layer and the stably stratified free atmosphere. The campaign took place at the Meteorological Observatory Lindenberg/Richard-Aßmann-Observatory of the German Meteorological Service. Besides the MAV flights, observations were made from a 12-m and a 99-m tower, a sodar, two ceilometers, radiosondes, and a tethered balloon with sensor packages at six different levels. MAV measurements were intentionally combined with remote sensing systems. The height range of the entrainment zone as well as its diurnal cycle were provided by the remote sensing instruments. The UAV provided the high-resolution in situ data of temperature and wind for the study of turbulent processes. It is shown that the MAV is able to maintain constant altitude with very small deviations—a pre-requisite to study processes inside the often quite thin entrainment zone and that MAV high-resolution wind and temperature measurements allow for very detailed studies of the fine structure of the atmosphere and thus for the identification of quite local and/or short-duration processes such as overshooting thermals or downward intrusions of warm air. Spatial series measured by the MAV during horizontal flights show turbulent exchange of heat in short turbulent bursts at heights close to and within the entrainment zone. Scaled vertical profiles of vertical velocity, potential temperature variance, and sensible heat flux confirm the general shape found by previous measurements and numerical studies.

  1. Powder synthesis and characterization of nanocrystalline CeO{sub 2} via the combustion processes

    SciTech Connect

    Gu Lina . E-mail: gln@mail.ustc.edu.cn; Meng Guangyao

    2007-07-03

    Nanocrystalline CeO{sub 2} powders were synthesized by the combustion reactions using citric acid and glycol as fuels and nitrate as an oxidant. The adiabatic flame temperatures in the auto ignition processes of the precursors were calculated theoretically. XRD measurements indicated that the powders produced in the combustion processes were cubic fluorite CeO{sub 2} phase. The size and morphology of the particles and extent of agglomeration in the powders were studied using transmission electron microscopy (TEM) and the particle size analyzer respectively. Blue shifts of the absorption peak of the as-prepared powders were observed.

  2. Processing of transparent polycrystalline AlON:Ce3+ scintillators

    DOE PAGESBeta

    Chen, Ching -Fong; Yang, Pin; King, Graham; Tegtmeier, Eric L.

    2015-10-23

    A new polycrystalline ceramic scintillator is reported for potential use in radiation detection and medical imaging applications. The goal was to develop cerium-activated aluminum oxynitride (AlON:Ce3+) ceramics, which can be produced using ceramic processes in comparison to the high-cost, low-yield single-crystal growth technique. A phase pure AlON:Ce3+ powder with cubic symmetry was successfully synthesized at high temperature under a reducing atmosphere to convert Ce4+ to Ce3+ in the solid solution. We explored two different activator concentrations (0.5 and 1.0 mol%). Fully dense and transparent AlON:Ce3+ ceramics were produced by a liquid-phase-assisted pressureless sintering. The crystal field splitting around the Ce3+more » activator in the AlON was comparable to the splitting induced by Br₋ and the Cl₋ ligands, which produced an emission spectrum perfectly matching the maximum quantum efficiency range of the photomultiplier tube for radiation detection. Both optical excitation and radiation ionizations in AlON:Ce3+ were demonstrated. Lastly, challenges and mechanisms related to the radioluminescence efficiency are discussed.« less

  3. Applicability of CeO 2 as a surrogate for PuO 2 in a MOX fuel development

    NASA Astrophysics Data System (ADS)

    Kim, Han Soo; Joung, Chang Yong; Lee, Byung Ho; Oh, Jae Yong; Koo, Yang Hyun; Heimgartner, Peter

    2008-08-01

    The applicability of cerium oxide, as a surrogate for plutonium oxide, was evaluated for the fabrication process of a MOX (mixed oxide) fuel pellet. Sintering behavior, pore former effect and thermal properties of the Ce-MOX were compared with those of Pu-MOX. Compacting parameters of the Pu-MOX powder were optimized by a simulation using Ce-MOX powder. Sintering behavior of Ce-MOX was very similar to that of Pu-MOX, in particular for the oxidative sintering process. The sintered density of both pellets was decreased with the same slope with an increasing DA (dicarbon amide) content. Both the Ce-MOX and Pu-MOX pellets which were fabricated by an admixing of 0.05 wt% DA and sintering in a CO 2 atmosphere had the same average grain size of 11 μm and a density of 95%T.D. The thermal conductivity of the Pu-MOX was a little higher than that of the Ce-MOX at a lower temperature but both conductivities became closer to each other above 900 K. Cerium oxide was found to be a useful surrogate to simulate the Pu behavior in the MOX fuel fabrication.

  4. Small scale processes and entrainment in a stratocumulus marine boundary layer

    SciTech Connect

    Stevens, D.E.; Almgren, A.S.; Bell, J.B.; Beckner, V.E.; Rendleman, C.A.

    1998-05-01

    Lack of resolution is a common problem hampering the use of large eddy simulation models for investigating boundary layer dynamics. Entrainment into the tops of marine stratus is characteristic of this problem. The use of parallel computing as a technique for resolving both boundary layer motions and the entrainment region enables the investigation of the interaction between the moist thermodynamics and turbulence in the entrainment region at very small length scales (dx = 8 m, dz = 4 m). This interaction results in heterogeneity at small scales which is important for correctly diagnosing the details of entrainment. This study presents several numerical experiments at high resolution using a generalization of a 1995 GCSS (GEWEX Cloud System Studies) model intercomparison. Subtle details of the numerical algorithm are found to cause larger differences in entrainment than choice of subgrid model. A kinetic energy budget shows that even for very high resolution, numerical dissipation is usually larger than that produced by the subgrid model. However, the structure of eddies at the inversion is determined mainly by resolution with very little dependence on numerical representation. Inversion properties are converging as resolution approaches an undulation scale. Most of the mixing is confined within 100 meters of the inversion with entraining motions having an aspect ratio of 6 to 1.

  5. Solution combustion synthesis of CeO{sub 2}-CeAlO{sub 3} nano-composites by mixture-of-fuels approach

    SciTech Connect

    Aruna, S.T.; Kini, N.S. Rajam, K.S.

    2009-04-02

    Nano-composites of CeO{sub 2}-CeAlO{sub 3} are synthesised by solution combustion method employing (a) urea and (b) a mixture of urea and glycine as fuels with corresponding metal nitrates. The as-prepared powders are all nano-sized (5-30 nm) and the same is confirmed by broadening of the X-ray diffraction peaks and transmission electron microscopy. A starting composition of Ce:Al in the atomic ratio 4:6 gives rise to different phases depending on the fuel being used for combustion. When urea alone is used as fuel, nano-crystalline CeO{sub 2} phase is formed with Al{sub 2}O{sub 3} being in the amorphous state. When the mixture of fuels is used, a mixture of nano-sized CeO{sub 2} and CeAlO{sub 3} phases is obtained. However, upon sintering at 1400 deg. C in air, the stable phases CeO{sub 2} and {alpha}-Al{sub 2}O{sub 3} are formed in both the cases. Combustion synthesis using mixture-of-fuels is proposed to be a route to stabilise low oxidation compounds such as CeAlO{sub 3}.

  6. Integrated coke, asphalt and jet fuel production process and apparatus

    DOEpatents

    Shang, Jer Y.

    1991-01-01

    A process and apparatus for the production of coke, asphalt and jet fuel m a feed of fossil fuels containing volatile carbon compounds therein is disclosed. The process includes the steps of pyrolyzing the feed in an entrained bed pyrolyzing means, separating the volatile pyrolysis products from the solid pyrolysis products removing at least one coke from the solid pyrolysis products, fractionating the volatile pyrolysis products to produce an overhead stream and a bottom stream which is useful as asphalt for road pavement, condensing the overhead stream to produce a condensed liquid fraction and a noncondensable, gaseous fraction, and removing water from the condensed liquid fraction to produce a jet fuel-containing product. The disclosed apparatus is useful for practicing the foregoing process. the process provides a useful method of mass producing and jet fuels from materials such as coal, oil shale and tar sands.

  7. Non-homogeneous hybrid rocket fuel for enhanced regression rates utilizing partial entrainment

    NASA Astrophysics Data System (ADS)

    Boronowsky, Kenny

    A concept was developed and tested to enhance the performance and regression rate of hydroxyl terminated polybutadiene (HTPB), a commonly used hybrid rocket fuel. By adding small nodules of paraffin into the HTPB fuel, a non-homogeneous mixture was created resulting in increased regression rates. The goal was to develop a fuel with a simplified single core geometry and a tailorable regression rate. The new fuel would benefit from the structural stability of HTPB yet not suffer from the large void fraction representative of typical HTPB core geometries. Regression rates were compared between traditional HTPB single core grains, 85% HTPB mixed with 15% (by weight) paraffin cores, 70% HTPB mixed with 30% paraffin cores, and plain paraffin single core grains. Each fuel combination was tested at oxidizer flow rates, ranging from 0.9 - 3.3 g/s of gaseous oxygen, in a small scale hybrid test rocket and average regression rates were measured. While large uncertainties were present in the experimental setup, the overall data showed that the regression rate was enhanced as paraffin concentration increased. While further testing would be required at larger scales of interest, the trends are encouraging. Inclusion of paraffin nodules in the HTPB grain may produce a greater advantage than other more noxious additives in current use. In addition, it may lead to safer rocket motors with higher integrated thrust due to the decreased void fraction.

  8. Measurements and modeling of pulverized fuel char in an entrained flow reactor

    NASA Astrophysics Data System (ADS)

    Kebria, Mazdak

    In recent years, the combustion zone of utility boilers were modified for NOx control and this made the task of maintaining low residual carbon levels in boiler fly ash much more difficult. To predict the relationships between boiler operating conditions and residual carbon-in-ash, there is a need for improvements in determining the appropriate char reactivity to use in simulating coal-fired combustors and in relating this reactivity to unburned coal characteristics. To aid in this effort, a tubular, downward-fired, refractory-lined, laminar entrained flow reactor (EFR) was built to provide a pilot scale environment with 2 seconds residence time for studying coal combustion. Using a commercial CFD code (FLUENT), a three dimensional numerical model of coal burning in the EFR was created to evaluate common char burnout kinetic modeling approaches. EFR experimental data was obtained for operating conditions adjusted to reproduce particle Lagrangian temperature and oxygen concentration time histories typically found in coal-fired utility boilers. The radial temperature profiles were measured at different axial locations in the EFR with a suction pyrometer and thermocouples. The temperature distribution in the reactor agreed well with the simulations. A gas analyzer with a quenching probe was used to measure the oxygen distribution to similarly confirm oxygen distribution in the EFR. A semi-isokinetic particulate sampling probe was used to extract ash samples at different heights in the reactor to measure the evolution of loss on ignition (LOI). Measured LOI values were used to validate the model against predicted values. Reaction kinetics rates in the model were adjusted to bring agreement between calculated LOI and the measured values from the experimental results. The LOI predictions by kinetic-diffusion and CBK model are very similar at the late stage of char burnout. The results indicate that we can achieve sufficient accuracy for the prediction of final carbon

  9. Inducing attention not to blink: auditory entrainment improves conscious visual processing.

    PubMed

    Ronconi, Luca; Pincham, Hannah L; Szűcs, Dénes; Facoetti, Andrea

    2016-09-01

    Our ability to allocate attention at different moments in time can sometimes fail to select stimuli occurring in close succession, preventing visual information from reaching awareness. This so-called attentional blink (AB) occurs when the second of two targets (T2) is presented closely after the first (T1) in a rapid serial visual presentation (RSVP). We hypothesized that entrainment to a rhythmic stream of stimuli-before visual targets appear-would reduce the AB. Experiment 1 tested the effect of auditory entrainment by presenting sounds with a regular or irregular interstimulus interval prior to a RSVP where T1 and T2 were separated by three possible lags (1, 3 and 8). Experiment 2 examined visual entrainment by presenting visual stimuli in place of auditory stimuli. Results revealed that irrespective of sensory modality, arrhythmic stimuli preceding the RSVP triggered an alerting effect that improved the T2 identification at lag 1, but impaired the recovery from the AB at lag 8. Importantly, only auditory rhythmic entrainment was effective in reducing the AB at lag 3. Our findings demonstrate that manipulating the pre-stimulus condition can reduce deficits in temporal attention characterizing the human cognitive architecture, suggesting innovative trainings for acquired and neurodevelopmental disorders. PMID:26215434

  10. Health Effects Associated with Inhalation Exposure to Diesel Emission Generated with and without CeO2 Nano Fuel Additive

    EPA Science Inventory

    Diesel exhaust (DE) exposure induces adverse cardiopulmonary effects. Addition of nano cerium (Ce) oxide additive to diesel fuel (DECe) increases fuel burning efficiency resulting in altered emission characteristics and potentially altered health effects. We hypothesized that inh...

  11. Spent graphite fuel element processing

    SciTech Connect

    Holder, N.D.; Olsen, C.W.

    1981-07-01

    The Department of Energy currently sponsors two programs to demonstrate the processing of spent graphite fuel elements. General Atomic in San Diego operates a cold pilot plant to demonstrate the processing of both US and German high-temperature reactor fuel. Exxon Nuclear Idaho Company is demonstrating the processing of spent graphite fuel elements from Rover reactors operated for the Nuclear Rocket Propulsion Program. This work is done at Idaho National Engineering Laboratory, where a hot facility is being constructed to complete processing of the Rover fuel. This paper focuses on the graphite combustion process common to both programs.

  12. Small-scale processes and entrainment in a stratocumulus marine boundary layer

    SciTech Connect

    Stevens, D.E.; Bell, J.B.; Almgren, A.S.; Beckner, V.E.; Rendleman, C.A.

    2000-02-15

    Numerical studies of boundary layer meteorology are increasingly reliant on large eddy simulation (LES) models, but few detailed validation studies of these types of models have been done. In this paper, the authors investigate the behavior of an LES model for simulation of a marine boundary layer. Specifically, the authors focus on the mechanisms that control numerical predictions of entrainment into the tops of marine stratus in a moist generalization of the 1995 Global Energy and Water Cycle Experiment Cloud System Studies model intercomparison. For the computational study the authors present a sequence of simulations of varying resolution, from a typical resolution (50 m horizontal and 25 m vertical mesh size) to a fine resolution (8 m horizontal and 4 m vertical mesh size). The authors also explore variations in the model such as different subgrid models and modifications of the advection scheme. It was found that the thickness of the inversion, the depth of entraining eddies, and the shape of vertical velocity spectra were determined mainly by the mesh spacing used. However, the entrainment rate was found to have a distinct dependence on the amount of combined numerical and subgrid-scale mixing. This indicates that the use of large eddy simulation to study mixing in stratocumulus boundary layers needs to account for both sources of mixing.

  13. Fuel processing device

    DOEpatents

    Ahluwalia, Rajesh K.; Ahmed, Shabbir; Lee, Sheldon H. D.

    2011-08-02

    An improved fuel processor for fuel cells is provided whereby the startup time of the processor is less than sixty seconds and can be as low as 30 seconds, if not less. A rapid startup time is achieved by either igniting or allowing a small mixture of air and fuel to react over and warm up the catalyst of an autothermal reformer (ATR). The ATR then produces combustible gases to be subsequently oxidized on and simultaneously warm up water-gas shift zone catalysts. After normal operating temperature has been achieved, the proportion of air included with the fuel is greatly diminished.

  14. Monolithic Fuel Fabrication Process Development

    SciTech Connect

    C. R. Clark; N. P. Hallinan; J. F. Jue; D. D. Keiser; J. M. Wight

    2006-05-01

    The pursuit of a high uranium density research reactor fuel plate has led to monolithic fuel, which possesses the greatest possible uranium density in the fuel region. Process developments in fabrication development include friction stir welding tool geometry and cooling improvements and a reduction in the length of time required to complete the transient liquid phase bonding process. Annealing effects on the microstructures of the U-10Mo foil and friction stir welded aluminum 6061 cladding are also examined.

  15. Oil production by entrained pyrolysis of biomass and processing of oil and char

    DOEpatents

    Knight, James A.; Gorton, Charles W.

    1990-01-02

    Entrained pyrolysis of lignocellulosic material proceeds from a controlled pyrolysis-initiating temperature to completion of an oxygen free environment at atmospheric pressure and controlled residence time to provide a high yield recovery of pyrolysis oil together with char and non-condensable, combustible gases. The residence time is a function of gas flow rate and the initiating temperature is likewise a function of the gas flow rate, varying therewith. A controlled initiating temperature range of about 400.degree. C. to 550.degree. C. with corresponding gas flow rates to maximize oil yield is disclosed.

  16. Development of a Ni-Ce0.8Zr0.2O2 catalyst for solid oxide fuel cells operating on ethanol through internal reforming

    NASA Astrophysics Data System (ADS)

    Liao, Mingming; Wang, Wei; Ran, Ran; Shao, Zongping

    2011-08-01

    Inexpensive 20 wt.% Ni-Ce0.8Zr0.2O2 catalysts are synthesized by a glycine nitrate process (GNP) and an impregnation process (IMP). The catalytic activity for ethanol steam reforming (ESR) at 400-650 °C, catalytic stability and carbon deposition properties are investigated. Ni-Ce0.8Zr0.2O2 (GNP) shows a higher catalytic performance than Ni-Ce0.8Zr0.2O2 (IMP), especially at lower temperatures. It also presents a better coking resistance and a lower graphitization degree of the deposited carbon. The superior catalytic activity and coke resistance of Ni-Ce0.8Zr0.2O2 (GNP) is attributed to the small particle size of the active metallic nickel phase and the strong interaction between the nickel and the Ce0.8Zr0.2O2 support, as evidenced by the XRD and H2-TPR. The Ni-Ce0.8Zr0.2O2 (GNP) is further applied as an anode functional layer in solid oxide fuel cells operating on ethanol steam. The cell yields a peak power density of 536 mW cm-2 at 700 °C when operating on EtOH-H2O gas mixtures, which is only slightly lower than that of hydrogen fuel, whereas the cell without the functional layer failed for short-term operations. Ni-Ce0.8Zr0.2O2 (GNP) is promising as an active and highly coking-resistant catalyst layer for solid-oxide fuel cells operating on ethanol steam fuel.

  17. Shaping process makes fuels

    SciTech Connect

    Tabak, S.A.; Krambeck, F.J.

    1985-09-01

    The Mobil Olefin to Gasoline and Distillate (MOGD) process is described in which light olefinic compunds can be converted to high quality gasoline and distillate. This process, now ready for commercialization is based on a unique synthetic zeolite catalyst, the shape of which selectively oligomerizes light olefins to higher molecular weight iso-olefins. The highly flexible process can be designed to produce distillate/gasoline ratios of 0/100 to 90/10 for a commercial plant, depending on market requirements. MOGD is applicable to a wide range of feed streams ranging from ethylene to 400 degrees F end point olefinic naphtha. The process has been tested using commercially produced catalyst in refinery-scale equipment.

  18. Clouds and entrainment. [cumulus convective turbulence in clear air

    NASA Technical Reports Server (NTRS)

    Randall, D. A.

    1982-01-01

    The concept of entrainment is discussed, and the knowledge that has been acquired about entraining turbulence in clear air is surveyed. Attention is then given to observations and models of stratocumulus entrainment, which show some of the ways in which cloudiness modifies the entrainment process. Entraining cumuli are also considered, with some of the differences between cumulus entrainment and stratocumulus entrainment noted. Emphasis is placed on the dynamical aspects of entrainment; its effects on droplet spectra and other microphysical aspects are mentioned only briefly.

  19. Role of Microstructure and Surface Defects on the Dissolution Kinetics of CeO2, a UO2 Fuel Analogue.

    PubMed

    Corkhill, Claire L; Bailey, Daniel J; Tocino, Florent Y; Stennett, Martin C; Miller, James A; Provis, John L; Travis, Karl P; Hyatt, Neil C

    2016-04-27

    The release of radionuclides from spent fuel in a geological disposal facility is controlled by the surface mediated dissolution of UO2 in groundwater. In this study we investigate the influence of reactive surface sites on the dissolution of a synthesized CeO2 analogue for UO2 fuel. Dissolution was performed on the following: CeO2 annealed at high temperature, which eliminated intrinsic surface defects (point defects and dislocations); CeO2-x annealed in inert and reducing atmospheres to induce oxygen vacancy defects and on crushed CeO2 particles of different size fractions. BET surface area measurements were used as an indicator of reactive surface site concentration. Cerium stoichiometry, determined using X-ray Photoelectron Spectroscopy (XPS) and supported by X-ray Diffraction (XRD) analysis, was used to determine oxygen vacancy concentration. Upon dissolution in nitric acid medium at 90 °C, a quantifiable relationship was established between the concentration of high energy surface sites and CeO2 dissolution rate; the greater the proportion of intrinsic defects and oxygen vacancies, the higher the dissolution rate. Dissolution of oxygen vacancy-containing CeO2-x gave rise to rates that were an order of magnitude greater than for CeO2 with fewer oxygen vacancies. While enhanced solubility of Ce(3+) influenced the dissolution, it was shown that replacement of vacancy sites by oxygen significantly affected the dissolution mechanism due to changes in the lattice volume and strain upon dissolution and concurrent grain boundary decohesion. These results highlight the significant influence of defect sites and grain boundaries on the dissolution kinetics of UO2 fuel analogues and reduce uncertainty in the long term performance of spent fuel in geological disposal. PMID:27022662

  20. Process for removal of sulfur compounds from fuel gases

    DOEpatents

    Moore, Raymond H.; Stegen, Gary E.

    1978-01-01

    Fuel gases such as those produced in the gasification of coal are stripped of sulfur compounds and particulate matter by contact with molten metal salt. The fuel gas and salt are intimately mixed by passage through a venturi or other constriction in which the fuel gas entrains the molten salt as dispersed droplets to a gas-liquid separator. The separated molten salt is divided into a major and a minor flow portion with the minor flow portion passing on to a regenerator in which it is contacted with steam and carbon dioxide as strip gas to remove sulfur compounds. The strip gas is further processed to recover sulfur. The depleted, minor flow portion of salt is passed again into contact with the fuel gas for further sulfur removal from the gas. The sulfur depleted, fuel gas then flows through a solid absorbent for removal of salt droplets. The minor flow portion of the molten salt is then recombined with the major flow portion for feed to the venturi.

  1. Design of Pt-CeOx hetero-interface on electrodes in polymer electrolyte membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Mori, T.; Fugane, K.; Chauhan, S.; Ito, M.; Masuda, T.; Noguchi, H.; Uosaki, K.

    2014-03-01

    Pt-CeOx interface on Pt electrodes was prepared for improvement of both oxygen reduction reaction (ORR) activity of Pt cathode and CO tolerance of Pt anode. The surface of Pt-CeOx nano-particle/C electrode mainly consists of metallic Pt, ionized Pt (i.e. Pt2+) and Ce3+ species. The ORR activity on Pt was improved by the formation of Pt-CeOx interface. In-situ XAFS analysis suggests that cerium oxide surface in the Pt-CeOx/C was oxidized instead of Pt surface by electrochemical redox reaction of CeOx at room temperature. This suggests that the Pt-CeOx interface plays key role for improvement of cathode performance. Also, CO tolerance of Pt was improved by the formation of aforementioned interface. The improvement of CO tolerance of Pt was also observed by using in-situ IR analysis. Based on all experimental data, it is concluded that the design of defect structure in Pt-CeOx provides us opportunity to make the breakthrough electrodes for fuel cell application.

  2. Processing sunflower oil for fuel

    SciTech Connect

    Backer, L.F.; Jacobsen, L.; Olson, C.

    1982-05-01

    Research on processing of sunflower seed for oil was initiated to evaluate the equipment that might adapt best to on-farm or small factory production facilities. The first devices identified for evaluation were auger press expeller units, primary oil cleaning equipment, and final filters. A series of standard finishing filtration tests were carried out on sunflower oil and sunflower oil - diesel fuel blends using sunflower oil from four different sources.

  3. Synthetic fuels handbook: properties, process and performance

    SciTech Connect

    Speight, J.

    2008-07-01

    The handbook is a comprehensive guide to the benefits and trade-offs of numerous alternative fuels, presenting expert analyses of the different properties, processes, and performance characteristics of each fuel. It discusses the concept systems and technology involved in the production of fuels on both industrial and individual scales. Chapters 5 and 7 are of special interest to the coal industry. Contents: Chapter 1. Fuel Sources - Conventional and Non-conventional; Chapter 2. Natural Gas; Chapter 3. Fuels From Petroleum and Heavy Oil; Chapter 4. Fuels From Tar Sand Bitumen; Chapter 5. Fuels From Coal; Chapter 6. Fuels From Oil Shale; Chapter 7. Fuels From Synthesis Gas; Chapter 8. Fuels From Biomass; Chapter 9. Fuels From Crops; Chapter 10. Fuels From Wood; Chapter 11. Fuels From Domestic and Industrial Waste; Chapter 12. Landfill Gas. 3 apps.

  4. Low-Frequency Cortical Entrainment to Speech Reflects Phoneme-Level Processing.

    PubMed

    Di Liberto, Giovanni M; O'Sullivan, James A; Lalor, Edmund C

    2015-10-01

    The human ability to understand speech is underpinned by a hierarchical auditory system whose successive stages process increasingly complex attributes of the acoustic input. It has been suggested that to produce categorical speech perception, this system must elicit consistent neural responses to speech tokens (e.g., phonemes) despite variations in their acoustics. Here, using electroencephalography (EEG), we provide evidence for this categorical phoneme-level speech processing by showing that the relationship between continuous speech and neural activity is best described when that speech is represented using both low-level spectrotemporal information and categorical labeling of phonetic features. Furthermore, the mapping between phonemes and EEG becomes more discriminative for phonetic features at longer latencies, in line with what one might expect from a hierarchical system. Importantly, these effects are not seen for time-reversed speech. These findings may form the basis for future research on natural language processing in specific cohorts of interest and for broader insights into how brains transform acoustic input into meaning. PMID:26412129

  5. Tracking cortical entrainment in neural activity: auditory processes in human temporal cortex

    PubMed Central

    Thwaites, Andrew; Nimmo-Smith, Ian; Fonteneau, Elisabeth; Patterson, Roy D.; Buttery, Paula; Marslen-Wilson, William D.

    2015-01-01

    A primary objective for cognitive neuroscience is to identify how features of the sensory environment are encoded in neural activity. Current auditory models of loudness perception can be used to make detailed predictions about the neural activity of the cortex as an individual listens to speech. We used two such models (loudness-sones and loudness-phons), varying in their psychophysiological realism, to predict the instantaneous loudness contours produced by 480 isolated words. These two sets of 480 contours were used to search for electrophysiological evidence of loudness processing in whole-brain recordings of electro- and magneto-encephalographic (EMEG) activity, recorded while subjects listened to the words. The technique identified a bilateral sequence of loudness processes, predicted by the more realistic loudness-sones model, that begin in auditory cortex at ~80 ms and subsequently reappear, tracking progressively down the superior temporal sulcus (STS) at lags from 230 to 330 ms. The technique was then extended to search for regions sensitive to the fundamental frequency (F0) of the voiced parts of the speech. It identified a bilateral F0 process in auditory cortex at a lag of ~90 ms, which was not followed by activity in STS. The results suggest that loudness information is being used to guide the analysis of the speech stream as it proceeds beyond auditory cortex down STS toward the temporal pole. PMID:25713530

  6. Characterization and ecological risk assessment of nanoparticulate CeO2 as a diesel fuel catalyst.

    PubMed

    Batley, Graeme E; Halliburton, Brendan; Kirby, Jason K; Doolette, Casey L; Navarro, Divina; McLaughlin, Mike J; Veitch, Colin

    2013-08-01

    Nanoparticulate cerium dioxide (nano-CeO2 ), when combusted as an additive to diesel fuel, was transformed from 6 nm to 14 nm sizes into particles near 43 nm, with no obvious change in the unit cell dimensions or crystalline form. Cerium sulfate, if formed during combustion, was below detection limits. Ceria nanoparticles were agglomerated within the soot matrix, with a mean aerodynamic diameter near 100 nm. The dissolution of cerium from the dried ceria catalyst in synthetic soft water was extremely small (<0.0006% or <0.2 µg Ce/L), with particles being highly agglomerated (<450 nm). Agglomeration was reduced in the presence of humic acid. In the combusted samples, soot was dominant, and the solubility of cerium in soft water showed an almost 100-fold increase in the <1 nm fraction compared to that before combustion. It appeared that the nano-CeO2 remained agglomerated within the soot matrix and would not be present as dispersed nanoparticles in aquatic or soil environments. Despite the increased dissolution, the solubility was not sufficient for the combusted ceria to represent a risk in aquatic ecosystems. The predicted environmental concentrations were still orders of magnitude below the predicted no effects concentration of near 1 mg/L. In the soil environment, any cerium released from soot materials would interact with natural colloids, decreasing cerium concentrations in soil solutions and further minimizing the potential risk to soil organisms. PMID:23595783

  7. Microbial fuel cell treatment of fuel process wastewater

    DOEpatents

    Borole, Abhijeet P; Tsouris, Constantino

    2013-12-03

    The present invention is directed to a method for cleansing fuel processing effluent containing carbonaceous compounds and inorganic salts, the method comprising contacting the fuel processing effluent with an anode of a microbial fuel ell, the anode containing microbes thereon which oxidatively degrade one or more of the carbonaceous compounds while producing electrical energy from the oxidative degradation, and directing the produced electrical energy to drive an electrosorption mechanism that operates to reduce the concentration of one or more inorganic salts in the fuel processing effluent, wherein the anode is in electrical communication with a cathode of the microbial fuel cell. The invention is also directed to an apparatus for practicing the method.

  8. Separation and detection of amino acid metabolites of Escherichia coli in microbial fuel cell with CE.

    PubMed

    Wang, Wei; Ma, Lihong; Lin, Ping; Xu, Kaixuan

    2016-07-01

    In this work, CE-LIF was employed to investigate the amino acid metabolites produced by Escherichia coli (E. coli) in microbial fuel cell (MFC). Two peptides, l-carnosine and l-alanyl-glycine, together with six amino acids, cystine, alanine, lysine, methionine, tyrosine, arginine were separated and detected in advance by a CE-LIF system coupled with a homemade spontaneous injection device. The injection device was devised to alleviate the effect of electrical discrimination for analytes during sample injection. All analytes could be completely separated within 8 min with detection limits of 20-300 nmol/L. Then this method was applied to analyze the substrate solution containing amino acid metabolites produced by E. coli. l-carnosine, l-alanyl-glycine, and cystine were used as the carbon, nitrogen, and sulfur source for the E. coli culture in the MFC to investigate the amino acid metabolites during metabolism. Two MFCs were used to compare the activity of metabolism of the bacteria. In the sample collected at the running time 200 h of MFC, the amino acid methionine was discovered as the metabolite with the concentrations 23.3 μg/L. PMID:27121957

  9. Nanostructured Gd-CeO2 electrolyte for solid oxide fuel cell by aqueous tape casting

    NASA Astrophysics Data System (ADS)

    Akbari-Fakhrabadi, A.; Mangalaraja, R. V.; Sanhueza, Felipe A.; Avila, Ricardo E.; Ananthakumar, S.; Chan, S. H.

    2012-11-01

    Gadolinia-doped ceria (Ce0.9Gd0.1O1.95, GDC) electrolyte was fabricated by aqueous-based tape casting method for solid oxide fuel cells (SOFCs). The ceramic powder prepared by combustion synthesis was used with poly acrylic acid (PAA), poly vinyl alcohol (PVA), poly ethylene glycol (PEG), Octanol, 2,4,7,9-tetramethyl-5-decyne-4,7-diol ethoxylate and double distilled water as dispersant, binder, plasticizer, defoamer, surfactant and solvent respectively, to prepare stable GDC slurry. The conditions for preparing stable GDC slurries were studied and optimized by sedimentation, zeta potential and viscosity measurements. Green tapes with smooth surface, flexibility, thickness in the range of 0.35-0.4 mm and 45% relative green density were prepared. Conventional and flash sintering techniques were used and compared for densification which demonstrated the possibility of surpassing sintering at high temperatures and retarding related grain growth.

  10. Fast Reactor Spent Fuel Processing: Experience and Criticality Safety

    SciTech Connect

    Chad Pope

    2007-05-01

    This paper discusses operational and criticality safety experience associated with the Idaho National Laboratory Fuel Conditioning Facility which uses a pyrometallurgical process to treat spent fast reactor metallic fuel. The process is conducted in an inert atmosphere hot cell. The process starts with chopping metallic fuel elements into a basket. The basket is lowered into molten salt (LiCl-KCl) along with a steel mandrel. Active metal fission products, transuranic metals and sodium metal in the spent fuel undergo chemical oxidation and form chlorides. Voltage is applied between the basket, which serves as an anode, and the mandrel, which serves as a cathode, causing metallic uranium in the spent fuel to undergo electro-chemical oxidation thereby forming uranium chloride. Simultaneously at the cathode, uranium chloride undergoes electro-chemical reduction and deposits uranium metal onto the mandrel. The uranium metal and accompanying entrained salt are placed in a distillation furnace where the uranium melts forming an ingot and the entrained salt boils and subsequently condenses in a separate crucible. The uranium ingots are placed in long term storage. During the ten year operating history, over one hundred criticality safety evaluations were prepared. All criticality safety related limits and controls for the entire process are contained in a single document which required over thirty revisions to accommodate the process changes. Operational implementation of the limits and controls includes use of a near real-time computerized tracking system. The tracking system uses an Oracle database coupled with numerous software applications. The computerized tracking system includes direct fuel handler interaction with every movement of material. Improvements to this system during the ten year history include introduction of web based operator interaction, tracking of moderator materials and the development of a plethora database queries to assist in day to day

  11. Processing of transparent polycrystalline AlON:Ce3+ scintillators

    SciTech Connect

    Chen, Ching -Fong; Yang, Pin; King, Graham; Tegtmeier, Eric L.

    2015-10-23

    A new polycrystalline ceramic scintillator is reported for potential use in radiation detection and medical imaging applications. The goal was to develop cerium-activated aluminum oxynitride (AlON:Ce3+) ceramics, which can be produced using ceramic processes in comparison to the high-cost, low-yield single-crystal growth technique. A phase pure AlON:Ce3+ powder with cubic symmetry was successfully synthesized at high temperature under a reducing atmosphere to convert Ce4+ to Ce3+ in the solid solution. We explored two different activator concentrations (0.5 and 1.0 mol%). Fully dense and transparent AlON:Ce3+ ceramics were produced by a liquid-phase-assisted pressureless sintering. The crystal field splitting around the Ce3+ activator in the AlON was comparable to the splitting induced by Br₋ and the Cl₋ ligands, which produced an emission spectrum perfectly matching the maximum quantum efficiency range of the photomultiplier tube for radiation detection. Both optical excitation and radiation ionizations in AlON:Ce3+ were demonstrated. Lastly, challenges and mechanisms related to the radioluminescence efficiency are discussed.

  12. Dry process dependency of dupic fuel cycle

    SciTech Connect

    Park, Kwangheon; Whang, Juho; Kim, Yun-goo; Kim, Heemoon

    1996-12-31

    During the Dry Process, volatile and semi-volatile elements are released from the fuel. The effects of these released radioactive nuclides on DUPIC fuel cycle are analyzed from the view-point of radiation hazard, decay beat, and hazard index. Radiation hazard of fresh and spent DUPIC fuel is sensitive to the method of Dry Process. Decay beat of the fuel is also affected. Hazard index turned out not to be dependent on Dry Process.

  13. Partial entrainment of gravel bars during floods

    USGS Publications Warehouse

    Konrad, C.P.; Booth, D.B.; Burges, S.J.; Montgomery, D.R.

    2002-01-01

    Spatial patterns of bed material entrainment by floods were documented at seven gravel bars using arrays of metal washers (bed tags) placed in the streambed. The observed patterns were used to test a general stochastic model that bed material entrainment is a spatially independent, random process where the probability of entrainment is uniform over a gravel bar and a function of the peak dimensionless shear stress ??*0 of the flood. The fraction of tags missing from a gravel bar during a flood, or partial entrainment, had an approximately normal distribution with respect to ??*0 with a mean value (50% of the tags entrained) of 0.085 and standard deviation of 0.022 (root-mean-square error of 0.09). Variation in partial entrainment for a given ??*0 demonstrated the effects of flow conditioning on bed strength, with lower values of partial entrainment after intermediate magnitude floods (0.065 < ??*0 < 0.08) than after higher magnitude floods. Although the probability of bed material entrainment was approximately uniform over a gravel bar during individual floods and independent from flood to flood, regions of preferential stability and instability emerged at some bars over the course of a wet season. Deviations from spatially uniform and independent bed material entrainment were most pronounced for reaches with varied flow and in consecutive floods with small to intermediate magnitudes.

  14. Parallel Signal Processing and System Simulation using aCe

    NASA Technical Reports Server (NTRS)

    Dorband, John E.; Aburdene, Maurice F.

    2003-01-01

    Recently, networked and cluster computation have become very popular for both signal processing and system simulation. A new language is ideally suited for parallel signal processing applications and system simulation since it allows the programmer to explicitly express the computations that can be performed concurrently. In addition, the new C based parallel language (ace C) for architecture-adaptive programming allows programmers to implement algorithms and system simulation applications on parallel architectures by providing them with the assurance that future parallel architectures will be able to run their applications with a minimum of modification. In this paper, we will focus on some fundamental features of ace C and present a signal processing application (FFT).

  15. Effect of oxidizer to fuel molar ratio on particle size and DC conductivity of CeO2 nanoparticles

    NASA Astrophysics Data System (ADS)

    Harish, B. M.; Rajeeva, M. P.; Naveen, C. S.; Chaturmukha, V. S.; Avinash, B. S.; Jayanna, H. S.; Lamani, Ashok R.

    2016-05-01

    Cerium oxide nanoparticles were synthesized by solution combustion method with varying the oxidizer (cerium nitrate hexa hydrate) to fuel (Glycine) molar ratio. The prepared samples were characterized by UV-visible spectrometer, X-ray diffractometer (XRD), Scanning electron microscope (SEM) and Energy dispersive X-Ray analysis (EDAX). XRD pattern reveals the formation of cubic fluorite structure of CeO2. It was observed that finest crystallites were found at extreme fuel-deficient condition and it is good enough to produce favorable powder characteristics. The average crystallite size was found to be 14.46 nm to 21.57 nm. The temperature dependent dc conductivity was carried out using Keithley source meter between the temperature range from 300K to 573K. From this study it was found that the conductivity increases with increase of temperature due to semiconducting behavior of CeO2 and it decreases with particle size due to increase in the energy band gap.

  16. Entrainment Rate in Shallow Cumuli: Dependence on Entrained Dry Air Sources and Probability Density Functions

    NASA Astrophysics Data System (ADS)

    Lu, C.; Liu, Y.; Niu, S.; Vogelmann, A. M.

    2012-12-01

    In situ aircraft cumulus observations from the RACORO field campaign are used to estimate entrainment rate for individual clouds using a recently developed mixing fraction approach. The entrainment rate is computed based on the observed state of the cloud core and the state of the air that is laterally mixed into the cloud at its edge. The computed entrainment rate decreases when the air is entrained from increasing distance from the cloud core edge; this is because the air farther away from cloud edge is drier than the neighboring air that is within the humid shells around cumulus clouds. Probability density functions of entrainment rate are well fitted by lognormal distributions at different heights above cloud base for different dry air sources (i.e., different source distances from the cloud core edge). Such lognormal distribution functions are appropriate for inclusion into future entrainment rate parameterization in large scale models. To the authors' knowledge, this is the first time that probability density functions of entrainment rate have been obtained in shallow cumulus clouds based on in situ observations. The reason for the wide spread of entrainment rate is that the observed clouds are affected by entrainment mixing processes to different extents, which is verified by the relationships between the entrainment rate and cloud microphysics/dynamics. The entrainment rate is negatively correlated with liquid water content and cloud droplet number concentration due to the dilution and evaporation in entrainment mixing processes. The entrainment rate is positively correlated with relative dispersion (i.e., ratio of standard deviation to mean value) of liquid water content and droplet size distributions, consistent with the theoretical expectation that entrainment mixing processes are responsible for microphysics fluctuations and spectral broadening. The entrainment rate is negatively correlated with vertical velocity and dissipation rate because entrainment

  17. A processing centre for the CNES CE-GPS experimentation

    NASA Technical Reports Server (NTRS)

    Suard, Norbert; Durand, Jean-Claude

    1994-01-01

    CNES is involved in a GPS (Global Positioning System) geostationary overlay experimentation. The purpose of this experimentation is to test various new techniques in order to select the optimal station synchronization method, as well as the geostationary spacecraft orbitography method. These new techniques are needed to develop the Ranging GPS Integrity Channel services. The CNES experimentation includes three transmitting/receiving ground stations (manufactured by IN-SNEC), one INMARSAT 2 C/L band transponder and a processing center named STE (Station de Traitements de l'Experimentation). Not all the techniques to be tested are implemented, but the experimental system has to include several functions; part of the future system simulation functions, such as a servo-loop function, and in particular a data collection function providing for rapid monitoring of system operation, analysis of existing ground station processes, and several weeks of data coverage for other scientific studies. This paper discusses system architecture and some criteria used in its design, as well as the monitoring function, the approach used to develop a low-cost and short-life processing center in collaboration with a CNES sub-contractor (ATTDATAID), and some results.

  18. Prediction and measurement of entrained flow coal gasification processes. Interim report, September 8, 1981-September 7, 1983

    SciTech Connect

    Hedman, P.O.; Smoot, L.D.; Fletcher, T.H.; Smith, P.J.; Blackham, A.U.

    1984-01-31

    This volume reports interim experimental and theoretical results of the first two years of a three year study of entrained coal gasification with steam and oxygen. The gasifier facility and testing methods were revised and improved. The gasifier was also modified for high pressure operation. Six successful check-out tests at elevated pressure were performed (55, 75, 100, 130, 170, and 215 psig), and 8 successful mapping tests were performed with the Utah bituminous coal at an elevated pressure of 137.5 psig. Also, mapping tests were performed at atmospheric pressure with a Utah bituminous coal (9 tests) and with a Wyoming subbituminous coal (14 tests). The LDV system was used on the cold-flow facility to make additional nonreactive jets mixing measurements (local mean and turbulent velocity) that could be used to help validate the two-dimensional code. The previously completed two-dimensional entrained coal gasification code, PCGC-2, was evaluated through rigorous comparison with cold-flow, pulverized coal combustion, and entrained coal gasification data. Data from this laboratory were primarily used but data from other laboratories were used when available. A complete set of the data used has been compiled into a Data Book which is included as a supplemental volume of this interim report. A revised user's manual for the two-dimensional code has been prepared and is also included as a part of this interim report. Three technical papers based on the results of this study were published or prepared. 107 references, 57 figures, 35 tables.

  19. Fuel quality processing study, volume 1

    NASA Astrophysics Data System (ADS)

    Ohara, J. B.; Bela, A.; Jentz, N. E.; Syverson, H. T.; Klumpe, H. W.; Kessler, R. E.; Kotzot, H. T.; Loran, B. L.

    1981-04-01

    A fuel quality processing study to provide a data base for an intelligent tradeoff between advanced turbine technology and liquid fuel quality, and also, to guide the development of specifications of future synthetic fuels anticipated for use in the time period 1985 to 2000 is given. Four technical performance tests are discussed: on-site pretreating, existing refineries to upgrade fuels, new refineries to upgrade fuels, and data evaluation. The base case refinery is a modern Midwest refinery processing 200,000 BPD of a 60/40 domestic/import petroleum crude mix. The synthetic crudes used for upgrading to marketable products and turbine fuel are shale oil and coal liquids. Of these syncrudes, 50,000 BPD are processed in the existing petroleum refinery, requiring additional process units and reducing petroleum feed, and in a new refinery designed for processing each syncrude to produce gasoline, distillate fuels, resid fuels, and turbine fuel, JPGs and coke. An extensive collection of synfuel properties and upgrading data was prepared for the application of a linear program model to investigate the most economical production slate meeting petroleum product specifications and turbine fuels of various quality grades. Technical and economic projections were developed for 36 scenarios, based on 4 different crude feeds to either modified existing or new refineries operated in 2 different modes to produce 7 differing grades of turbine fuels. A required product selling price of turbine fuel for each processing route was calculated. Procedures and projected economics were developed for on-site treatment of turbine fuel to meet limitations of impurities and emission of pollutants.

  20. Fuel quality processing study, volume 1

    NASA Technical Reports Server (NTRS)

    Ohara, J. B.; Bela, A.; Jentz, N. E.; Syverson, H. T.; Klumpe, H. W.; Kessler, R. E.; Kotzot, H. T.; Loran, B. L.

    1981-01-01

    A fuel quality processing study to provide a data base for an intelligent tradeoff between advanced turbine technology and liquid fuel quality, and also, to guide the development of specifications of future synthetic fuels anticipated for use in the time period 1985 to 2000 is given. Four technical performance tests are discussed: on-site pretreating, existing refineries to upgrade fuels, new refineries to upgrade fuels, and data evaluation. The base case refinery is a modern Midwest refinery processing 200,000 BPD of a 60/40 domestic/import petroleum crude mix. The synthetic crudes used for upgrading to marketable products and turbine fuel are shale oil and coal liquids. Of these syncrudes, 50,000 BPD are processed in the existing petroleum refinery, requiring additional process units and reducing petroleum feed, and in a new refinery designed for processing each syncrude to produce gasoline, distillate fuels, resid fuels, and turbine fuel, JPGs and coke. An extensive collection of synfuel properties and upgrading data was prepared for the application of a linear program model to investigate the most economical production slate meeting petroleum product specifications and turbine fuels of various quality grades. Technical and economic projections were developed for 36 scenarios, based on 4 different crude feeds to either modified existing or new refineries operated in 2 different modes to produce 7 differing grades of turbine fuels. A required product selling price of turbine fuel for each processing route was calculated. Procedures and projected economics were developed for on-site treatment of turbine fuel to meet limitations of impurities and emission of pollutants.

  1. Dry Processing of Used Nuclear Fuel

    SciTech Connect

    K. M. Goff; M. F. Simpson

    2009-09-01

    Dry (non-aqueous) separations technologies have been used for treatment of used nuclear fuel since the 1960s, and they are still being developed and demonstrated in many countries. Dry technologies offer potential advantages compared to traditional aqueous separations including: compactness, resistance to radiation effects, criticality control benefits, compatibility with advanced fuel types, and ability to produce low purity products. Within the Department of Energy’s Advanced Fuel Cycle Initiative, an electrochemical process employing molten salts is being developed for recycle of fast reactor fuel and treatment of light water reactor oxide fuel to produce a feed for fast reactors. Much of the development of this technology is based on treatment of used Experimental Breeder Reactor II (EBR-II) fuel, which is metallic. Electrochemical treatment of the EBR-II fuel has been ongoing in the Fuel Conditioning Facility, located at the Materials and Fuel Complex of Idaho National Laboratory since 1996. More than 3.8 metric tons of heavy metal of metallic fast reactor fuel have been treated using this technology. This paper will summarize the status of electrochemical development and demonstration activities with used nuclear fuel, including high-level waste work. A historic perspective on the background of dry processing will also be provided.

  2. Powder handling for automated fuel processing

    SciTech Connect

    Frederickson, J.R.; Eschenbaum, R.C.; Goldmann, L.H.

    1989-04-09

    Installation of the Secure Automated Fabrication (SAF) line has been completed. It is located in the Fuel Cycle Plant (FCP) at the Department of Energy's (DOE) Hanford site near Richland, Washington. The SAF line was designed to fabricate advanced reactor fuel pellets and assemble fuel pins by automated, remote operation. This paper describes powder handling equipment and techniques utilized for automated powder processing and powder conditioning systems in this line. 9 figs.

  3. Mathematical modeling of biomass fuels formation process

    SciTech Connect

    Gaska, Krzysztof Wandrasz, Andrzej J.

    2008-07-01

    The increasing demand for thermal and electric energy in many branches of industry and municipal management accounts for a drastic diminishing of natural resources (fossil fuels). Meanwhile, in numerous technical processes, a huge mass of wastes is produced. A segregated and converted combustible fraction of the wastes, with relatively high calorific value, may be used as a component of formed fuels. The utilization of the formed fuel components from segregated groups of waste in associated processes of co-combustion with conventional fuels causes significant savings resulting from partial replacement of fossil fuels, and reduction of environmental pollution resulting directly from the limitation of waste migration to the environment (soil, atmospheric air, surface and underground water). The realization of technological processes with the utilization of formed fuel in associated thermal systems should be qualified by technical criteria, which means that elementary processes as well as factors of sustainable development, from a global viewpoint, must not be disturbed. The utilization of post-process waste should be preceded by detailed technical, ecological and economic analyses. In order to optimize the mixing process of fuel components, a mathematical model of the forming process was created. The model is defined as a group of data structures which uniquely identify a real process and conversion of this data in algorithms based on a problem of linear programming. The paper also presents the optimization of parameters in the process of forming fuels using a modified simplex algorithm with a polynomial worktime. This model is a datum-point in the numerical modeling of real processes, allowing a precise determination of the optimal elementary composition of formed fuels components, with assumed constraints and decision variables of the task.

  4. Fuel quality/processing study. Volume 3: Fuel upgrading studies

    NASA Technical Reports Server (NTRS)

    Jones, G. E., Jr.; Bruggink, P.; Sinnett, C.

    1981-01-01

    The methods used to calculate the refinery selling prices for the turbine fuels of low quality are described. Detailed descriptions and economics of the upgrading schemes are included. These descriptions include flow diagrams showing the interconnection between processes and the stream flows involved. Each scheme is in a complete, integrated, stand alone facility. Except for the purchase of electricity and water, each scheme provides its own fuel and manufactures, when appropriate, its own hydrogen.

  5. Hydrodynamic Simulations of H Entrainment at the Top of He-shell Flash Convection

    NASA Astrophysics Data System (ADS)

    Woodward, Paul R.; Herwig, Falk; Lin, Pei-Hung

    2015-01-01

    We present the first three-dimensional, fully compressible gas-dynamics simulations in 4π geometry of He-shell flash convection with proton-rich fuel entrainment at the upper boundary. This work is motivated by the insufficiently understood observed consequences of the H-ingestion flash in post-asymptotic giant branch (post-AGB) stars (Sakurai's object) and metal-poor AGB stars. Our investigation is focused on the entrainment process at the top convection boundary and on the subsequent advection of H-rich material into deeper layers, and we therefore ignore the burning of the proton-rich fuel in this study. We find that for our deep convection zone, coherent convective motions of near global scale appear to dominate the flow. At the top boundary convective shear flows are stable against Kelvin-Helmholtz instabilities. However, such shear instabilities are induced by the boundary-layer separation in large-scale, opposing flows. This links the global nature of thick shell convection with the entrainment process. We establish the quantitative dependence of the entrainment rate on grid resolution. With our numerical technique, simulations with 10243 cells or more are required to reach a numerical fidelity appropriate for this problem. However, only the result from the 15363 simulation provides a clear indication that we approach convergence with regard to the entrainment rate. Our results demonstrate that our method, which is described in detail, can provide quantitative results related to entrainment and convective boundary mixing in deep stellar interior environments with very stiff convective boundaries. For the representative case we study in detail, we find an entrainment rate of 4.38 ± 1.48 × 10-13 M ⊙ s-1.

  6. HYDRODYNAMIC SIMULATIONS OF H ENTRAINMENT AT THE TOP OF He-SHELL FLASH CONVECTION

    SciTech Connect

    Woodward, Paul R.; Lin, Pei-Hung; Herwig, Falk E-mail: fherwig@uvic.ca

    2015-01-01

    We present the first three-dimensional, fully compressible gas-dynamics simulations in 4π geometry of He-shell flash convection with proton-rich fuel entrainment at the upper boundary. This work is motivated by the insufficiently understood observed consequences of the H-ingestion flash in post-asymptotic giant branch (post-AGB) stars (Sakurai's object) and metal-poor AGB stars. Our investigation is focused on the entrainment process at the top convection boundary and on the subsequent advection of H-rich material into deeper layers, and we therefore ignore the burning of the proton-rich fuel in this study. We find that for our deep convection zone, coherent convective motions of near global scale appear to dominate the flow. At the top boundary convective shear flows are stable against Kelvin-Helmholtz instabilities. However, such shear instabilities are induced by the boundary-layer separation in large-scale, opposing flows. This links the global nature of thick shell convection with the entrainment process. We establish the quantitative dependence of the entrainment rate on grid resolution. With our numerical technique, simulations with 1024{sup 3} cells or more are required to reach a numerical fidelity appropriate for this problem. However, only the result from the 1536{sup 3} simulation provides a clear indication that we approach convergence with regard to the entrainment rate. Our results demonstrate that our method, which is described in detail, can provide quantitative results related to entrainment and convective boundary mixing in deep stellar interior environments with very stiff convective boundaries. For the representative case we study in detail, we find an entrainment rate of 4.38 ± 1.48 × 10{sup –13} M {sub ☉} s{sup –1}.

  7. Prediction and measurement of optimum operating conditions for entrained coal gasification processes. Quarterly technical progress report, No. 1, 1 November 1979-31 January 1980

    SciTech Connect

    Smoot, L.D.; Hedman, P.O.; Smith, P.J.

    1980-02-15

    This report summarizes work completed to predict and measure optimum operating conditions for entrained coal gasifications processes. This study is the third in a series designed to investigate mixing and reaction in entrained coal gasifiers. A new team of graduate and undergraduate students was formed to conduct the experiments on optimum gasification operating conditions. Additional coal types, which will be tested in the gasifier were identified, ordered, and delivered. Characterization of these coals will be initiated. Hardware design modifications to introduce swirl into the secondary were initiated. Minor modifications were made to the gasifier to allow laser diagnostics to be made on an independently funded study with the Los Alamos Scientific Laboratory. The tasks completed on the two-dimensional model included the substantiation of a Gaussian PDF for the top-hat PDF in BURN and the completion of a Lagrangian particle turbulent dispersion module. The reacting submodel is progressing into the final stages of debug. The formulation of the radiation submodel is nearly complete and coding has been initiated. A device was designed, fabricated, and used to calibrate the actual Swirl Number of the cold-flow swirl generator used in the Phase 2 study. Swirl calibrations were obtained at the normal tests flow rates and at reduced flow rates. Two cold-flow tests were also performed to gather local velocity data under swirling conditions. Further analysis of the cold-flow coal-dust and swirl test results from the previous Phase 2 study were completed.

  8. Process for vaporizing a liquid hydrocarbon fuel

    DOEpatents

    Szydlowski, Donald F.; Kuzminskas, Vaidotas; Bittner, Joseph E.

    1981-01-01

    The object of the invention is to provide a process for vaporizing liquid hydrocarbon fuels efficiently and without the formation of carbon residue on the apparatus used. The process includes simultaneously passing the liquid fuel and an inert hot gas downwardly through a plurality of vertically spaed apart regions of high surface area packing material. The liquid thinly coats the packing surface, and the sensible heat of the hot gas vaporizes this coating of liquid. Unvaporized liquid passing through one region of packing is uniformly redistributed over the top surface of the next region until all fuel has been vaporized using only the sensible heat of the hot gas stream.

  9. CeO2 nanocubes-graphene oxide as durable and highly active catalyst support for proton exchange membrane fuel cell

    PubMed Central

    Lei, M.; Wang, Z. B.; Li, J. S.; Tang, H. L.; Liu, W. J.; Wang, Y. G.

    2014-01-01

    Rapid degradation of cell performance still remains a significant challenge for proton exchange membrane fuel cell (PEMFC). In this work, we develop novel CeO2 nanocubes-graphene oxide nanocomposites as durable and highly active catalyst support for proton exchange membrane fuel cell. We show that the use of CeO2 as the radical scavenger in the catalysts remarkably improves the durability of the catalyst. The catalytic activity retention of Pt-graphene oxide-8 wt.% CeO2 nanocomposites reaches as high as 69% after 5000 CV-cycles at a high voltage range of 0.8–1.23 V, in contrast to 19% for that of the Pt-graphene oxide composites. The excellent durability of the Pt-CeO2 nanocubes-graphene oxide catalyst is attributed to the free radical scavenging activity of CeO2, which significantly slows down the chemical degradation of Nafion binder in catalytic layers, and then alleviates the decay of Pt catalysts, resulting in the excellent cycle life of Pt-CeO2-graphene oxide nanocomposite catalysts. Additionally, the performance of single cell assembled with Nafion 211 membrane and Pt-CeO2-graphene oxide catalysts with different CeO2 contents in the cathode as well as the Pt-C catalysts in the anode are also recorded and discussed in this study. PMID:25491655

  10. Process for preparing a liquid fuel composition

    DOEpatents

    Singerman, Gary M.

    1982-03-16

    A process for preparing a liquid fuel composition which comprises liquefying coal, separating a mixture of phenols from said liquefied coal, converting said phenols to the corresponding mixture of anisoles, subjecting at least a portion of the remainder of said liquefied coal to hydrotreatment, subjecting at least a portion of said hydrotreated liquefied coal to reforming to obtain reformate and then combining at least a portion of said anisoles and at least a portion of said reformate to obtain said liquid fuel composition.

  11. Biomass conversion processes for energy and fuels

    NASA Astrophysics Data System (ADS)

    Sofer, S. S.; Zaborsky, O. R.

    The book treats biomass sources, promising processes for the conversion of biomass into energy and fuels, and the technical and economic considerations in biomass conversion. Sources of biomass examined include crop residues and municipal, animal and industrial wastes, agricultural and forestry residues, aquatic biomass, marine biomass and silvicultural energy farms. Processes for biomass energy and fuel conversion by direct combustion (the Andco-Torrax system), thermochemical conversion (flash pyrolysis, carboxylolysis, pyrolysis, Purox process, gasification and syngas recycling) and biochemical conversion (anaerobic digestion, methanogenesis and ethanol fermentation) are discussed, and mass and energy balances are presented for each system.

  12. SOFC system with integrated catalytic fuel processing

    NASA Astrophysics Data System (ADS)

    Finnerty, Caine; Tompsett, Geoff. A.; Kendall, Kevin; Ormerod, R. Mark

    In recent years, there has been much interest in the development of solid oxide fuel cell technology operating directly on hydrocarbon fuels. The development of a catalytic fuel processing system, which is integrated with the solid oxide fuel cell (SOFC) power source is outlined here. The catalytic device utilises a novel three-way catalytic system consisting of an in situ pre-reformer catalyst, the fuel cell anode catalyst and a platinum-based combustion catalyst. The three individual catalytic stages have been tested in a model catalytic microreactor. Both temperature-programmed and isothermal reaction techniques have been applied. Results from these experiments were used to design the demonstration SOFC unit. The apparatus used for catalytic characterisation can also perform in situ electrochemical measurements as described in previous papers [C.M. Finnerty, R.H. Cunningham, K. Kendall, R.M. Ormerod, Chem. Commun. (1998) 915-916; C.M. Finnerty, N.J. Coe, R.H. Cunningham, R.M. Ormerod, Catal. Today 46 (1998) 137-145]. This enabled the performance of the SOFC to be determined at a range of temperatures and reaction conditions, with current output of 290 mA cm -2 at 0.5 V, being recorded. Methane and butane have been evaluated as fuels. Thus, optimisation of the in situ partial oxidation pre-reforming catalyst was essential, with catalysts producing high H 2/CO ratios at reaction temperatures between 873 K and 1173 K being chosen. These included Ru and Ni/Mo-based catalysts. Hydrocarbon fuels were directly injected into the catalytic SOFC system. Microreactor measurements revealed the reaction mechanisms as the fuel was transported through the three-catalyst device. The demonstration system showed that the fuel processing could be successfully integrated with the SOFC stack.

  13. An integrated process for hydrogen-rich gas production from cotton stalks: The simultaneous gasification of pyrolysis gases and char in an entrained flow bed reactor.

    PubMed

    Chen, Zhiyuan; Zhang, Suping; Chen, Zhenqi; Ding, Ding

    2015-12-01

    An integrated process (pyrolysis, gas-solid simultaneous gasification and catalytic steam reforming) was utilized to produce hydrogen-rich gas from cotton stalks. The simultaneous conversion of the pyrolysis products (char and pyrolysis gases) was emphatically investigated using an entrained flow bed reactor. More carbon of char is converted into hydrogen-rich gas in the simultaneous conversion process and the carbon conversion is increased from 78.84% to 92.06% compared with the two stages process (pyrolysis and catalytic steam reforming). The distribution of tar components is also changed in this process. The polycyclic aromatic compounds (PACs) of tar are converted into low-ring compounds or even chain compounds due to the catalysis of char. In addition, the carbon deposition yield over NiO/MgO catalyst in the steam reforming process is approximately 4 times higher without the simultaneous process. The potential H2 yield increases from 47.71 to 78.19g/kg cotton stalks due to the simultaneous conversion process. PMID:26433156

  14. Exploring Entrainment Patterns of Human Emotion in Social Media

    PubMed Central

    Luo, Chuan; Zhang, Zhu

    2016-01-01

    Emotion entrainment, which is generally defined as the synchronous convergence of human emotions, performs many important social functions. However, what the specific mechanisms of emotion entrainment are beyond in-person interactions, and how human emotions evolve under different entrainment patterns in large-scale social communities, are still unknown. In this paper, we aim to examine the massive emotion entrainment patterns and understand the underlying mechanisms in the context of social media. As modeling emotion dynamics on a large scale is often challenging, we elaborate a pragmatic framework to characterize and quantify the entrainment phenomenon. By applying this framework on the datasets from two large-scale social media platforms, we find that the emotions of online users entrain through social networks. We further uncover that online users often form their relations via dual entrainment, while maintain it through single entrainment. Remarkably, the emotions of online users are more convergent in nonreciprocal entrainment. Building on these findings, we develop an entrainment augmented model for emotion prediction. Experimental results suggest that entrainment patterns inform emotion proximity in dyads, and encoding their associations promotes emotion prediction. This work can further help us to understand the underlying dynamic process of large-scale online interactions and make more reasonable decisions regarding emergency situations, epidemic diseases, and political campaigns in cyberspace. PMID:26953692

  15. Exploring Entrainment Patterns of Human Emotion in Social Media.

    PubMed

    He, Saike; Zheng, Xiaolong; Zeng, Daniel; Luo, Chuan; Zhang, Zhu

    2016-01-01

    Emotion entrainment, which is generally defined as the synchronous convergence of human emotions, performs many important social functions. However, what the specific mechanisms of emotion entrainment are beyond in-person interactions, and how human emotions evolve under different entrainment patterns in large-scale social communities, are still unknown. In this paper, we aim to examine the massive emotion entrainment patterns and understand the underlying mechanisms in the context of social media. As modeling emotion dynamics on a large scale is often challenging, we elaborate a pragmatic framework to characterize and quantify the entrainment phenomenon. By applying this framework on the datasets from two large-scale social media platforms, we find that the emotions of online users entrain through social networks. We further uncover that online users often form their relations via dual entrainment, while maintain it through single entrainment. Remarkably, the emotions of online users are more convergent in nonreciprocal entrainment. Building on these findings, we develop an entrainment augmented model for emotion prediction. Experimental results suggest that entrainment patterns inform emotion proximity in dyads, and encoding their associations promotes emotion prediction. This work can further help us to understand the underlying dynamic process of large-scale online interactions and make more reasonable decisions regarding emergency situations, epidemic diseases, and political campaigns in cyberspace. PMID:26953692

  16. Nd1.8Ce0.2CuO4+δ:Ce0.9Gd0.1O2-δ as a composite cathode for intermediate-temperature solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Khandale, A. P.; Bhoga, S. S.

    2014-12-01

    The (100 - x)Nd1.8Ce0.2CuO4+δ:(x)Ce0.9Gd0.1O2-δ (x = 00, 10, 20 and 30 vol.%) composite systems are obtained by impregnating a stoichiometric solution of cerium and gadolinium nitrates followed by sintering at 900 °C for 4 h. Impregnating the Ce0.9Gd0.1O2-δ not only inhibits the growth of the host Nd1.8Ce0.2CuO4+δ grains during sintering but also enlarges the oxygen reduction reaction zone by introducing a nanosized phase that is ionically conductive, which significantly decreases the electrode polarization resistance of the composite cathode. A minimum polarization resistance value of 0.23 ± 0.02 Ω cm2 is obtained at 700 °C for a (80)Nd1.8Ce0.2CuO4+δ:(20)Ce0.9Gd0.1O2-δ composite cathode, and this value is attributed to the optimal dispersion into the porous Nd1.8Ce0.2CuO4+δ matrix. The impedance spectra are modeled using an electrical equivalent model that consists of a mid-frequency ZR1 -CPE circuit (parallel combination of R1 and constant phase element (CPE)) and a low-frequency Gerischer impedance. The Gerischer impedance decreases significantly when Ce0.9Gd0.1O2-δ infiltrates the Nd1.8Ce0.2CuO4+δ matrix. The oxygen partial pressure-dependent polarization study suggests a medium-frequency response, which is due to charge transfer step; however, the low-frequency response corresponds to the non-charge transfer oxygen adsorption-desorption and the diffusion process during the overall oxygen reduction reaction process.

  17. Ultra-Deep Adsorptive Desulfurization of Light-Irradiated Diesel Fuel over Supported TiO2-CeO2 Adsorbents

    SciTech Connect

    Xiao, Jing; Wang, Xiaoxing; Chen, Yongsheng; Fujii, Mamoru; Song, Chunshan

    2014-02-13

    This study investigates ultra-deep adsorptive desulfurization (ADS) from light-irradiated diesel fuel over supported TiO2CeO2 adsorbents. A 30-fold higher desulfurization capacity of 95 mL of fuel per gram of adsorbent (mL-F/g-sorb) or 1.143 mg of sulfur per gram of adsorbent (mg-S/g-sorb) was achieved from light-irradiated fuel over the original low-sulfur fuel containing about 15 ppm by weight (ppmw) of sulfur. The sulfur species on spent TiO2CeO2/MCM-48 adsorbent was identified by sulfur K-edge XANES as sulfones and the adsorption selectivity to different compounds tested in a model fuel decreases in the order of indole > dibenzothiophenesulfone → dibenzothiophene > 4-methyldibenzothiophene > benzothiophene > 4,6-dimethyldibenzothiophene > phenanthrene > 2-methylnaphthalene ~ fluorene > naphthalene. The results suggest that during ADS of light-irradiated fuel, the original sulfur species were chemically transformed to sulfones, resulting in the significant increase in desulfurization capacity. For different supports for TiO2–CeO2 oxides, the ADS capacity increases with a decrease in the point of zero charge (PZC) value; for silica-supported TiO2CeO2 oxides (the lowest PZC value of 2–4) with different surface areas, the ADS capacity increases monotonically with increasing surface area. The supported TiO2CeO2/MCM-48 adsorbent can be regenerated using oxidative air treatment. The present study provides an attractive new path to achieve ultraclean fuel more effectively.

  18. Entrainment across density interfaces

    NASA Astrophysics Data System (ADS)

    Sanchez, M. A.; Carrillo, A.; Mahjoub, O. B.

    2010-05-01

    The structure of non-homogeneous turbulence affected by stratification and rotation is investigated both by means of laboratory and numerical experiments. The experiments investigate zero mean flow across a stably stratified density interface and are used to quantify the entrainment, the mixing efficiency and different types of dominant instability and the topological aspects of the turbulent cascades detected both horizontally and vertically [1,2]. Grid turbulence in a rotating stratified two layer system is measured with PIV as well as with sonic velocimetry. Observations of the horizontal and vertical velocity energy spectra as well as the structure functions are used to estimate local mixedness, entrainment and intermittency [3,4]. The method of estimation of the average eddy diffusivity from the time series images of a sharp density interface marked by fluoresceine also take anisotropy into account. but on the long run, horizontal ( and 2D type flow such as [5]) flow directions will average out so using a single integral length scale defined in Sanchez and Redondo(1998) varying in height will be enough together with the internal frequency. The method of calculating vertical fluxes in time allows to estimate different intermittency parameters as a function of local instability e.g. Kelvin/Helmholtz, Rayleigh-Taylor or Holbmoe[6-8]. Different concentration interfaces show different fractal dimensions, that are also a power function of the local Richardson number, this may be due to different levels of intermittency and thus different spectra, which are not necessarily inertial nor in equilibrium [8,9]. [1] Sanchez M.A. and Redondo J.M.Observations from Grid Stirred Turbulence. Applied Scientific Research 59, 191-204. 1998. [2] Redondo, J.M. and Cantalapiedra I.R. Mixing in Horizontally Heterogeneous Flows . Jour. Flow Turbulence and Combustion. 51, 217-222. 1993. [3] Castilla R, Redondo J.M., Gamez P.J., Babiano A. Coherent vortices and Lagrangian Dynamics in 2D

  19. Alternative Fuel for Portland Cement Processing

    SciTech Connect

    Schindler, Anton K; Duke, Steve R; Burch, Thomas E; Davis, Edward W; Zee, Ralph H; Bransby, David I; Hopkins, Carla; Thompson, Rutherford L; Duan, Jingran; Venkatasubramanian, Vignesh; Stephen, Giles

    2012-06-30

    The production of cement involves a combination of numerous raw materials, strictly monitored system processes, and temperatures on the order of 1500 °C. Immense quantities of fuel are required for the production of cement. Traditionally, energy from fossil fuels was solely relied upon for the production of cement. The overarching project objective is to evaluate the use of alternative fuels to lessen the dependence on non-renewable resources to produce portland cement. The key objective of using alternative fuels is to continue to produce high-quality cement while decreasing the use of non-renewable fuels and minimizing the impact on the environment. Burn characteristics and thermodynamic parameters were evaluated with a laboratory burn simulator under conditions that mimic those in the preheater where the fuels are brought into a cement plant. A drop-tube furnace and visualization method were developed that show potential for evaluating time- and space-resolved temperature distributions for fuel solid particles and liquid droplets undergoing combustion in various combustion atmospheres. Downdraft gasification has been explored as a means to extract chemical energy from poultry litter while limiting the throughput of potentially deleterious components with regards to use in firing a cement kiln. Results have shown that the clinkering is temperature independent, at least within the controllable temperature range. Limestone also had only a slight effect on the fusion when used to coat the pellets. However, limestone addition did display some promise in regards to chlorine capture, as ash analyses showed chlorine concentrations of more than four times greater in the limestone infused ash as compared to raw poultry litter. A reliable and convenient sampling procedure was developed to estimate the combustion quality of broiler litter that is the best compromise between convenience and reliability by means of statistical analysis. Multi-day trial burns were conducted

  20. Physiology of circadian entrainment.

    PubMed

    Golombek, Diego A; Rosenstein, Ruth E

    2010-07-01

    Mammalian circadian rhythms are controlled by endogenous biological oscillators, including a master clock located in the hypothalamic suprachiasmatic nuclei (SCN). Since the period of this oscillation is of approximately 24 h, to keep synchrony with the environment, circadian rhythms need to be entrained daily by means of Zeitgeber ("time giver") signals, such as the light-dark cycle. Recent advances in the neurophysiology and molecular biology of circadian rhythmicity allow a better understanding of synchronization. In this review we cover several aspects of the mechanisms for photic entrainment of mammalian circadian rhythms, including retinal sensitivity to light by means of novel photopigments as well as circadian variations in the retina that contribute to the regulation of retinal physiology. Downstream from the retina, we examine retinohypothalamic communication through neurotransmitter (glutamate, aspartate, pituitary adenylate cyclase-activating polypeptide) interaction with SCN receptors and the resulting signal transduction pathways in suprachiasmatic neurons, as well as putative neuron-glia interactions. Finally, we describe and analyze clock gene expression and its importance in entrainment mechanisms, as well as circadian disorders or retinal diseases related to entrainment deficits, including experimental and clinical treatments. PMID:20664079

  1. Nanoporous silver cathode surface treated by atomic layer deposition of CeO(x) for low-temperature solid oxide fuel cells.

    PubMed

    Neoh, Ke Chean; Han, Gwon Deok; Kim, Manjin; Kim, Jun Woo; Choi, Hyung Jong; Park, Suk Won; Shim, Joon Hyung

    2016-05-01

    We evaluated the performance of solid oxide fuel cells (SOFCs) with a 50 nm thin silver (Ag) cathode surface treated with cerium oxide (CeO(x)) by atomic layer deposition (ALD). The performances of bare and ALD-treated Ag cathodes were evaluated on gadolinia-doped ceria (GDC) electrolyte supporting cells with a platinum (Pt) anode over 300 °C-450 °C. Our work confirms that ALD CeO(x) treatment enhances cathodic performance and thermal stability of the Ag cathode. The performance difference between cells using a Ag cathode optimally treated with an ALD CeO(x) surface and a reference Pt cathode is about 50% at 450 °C in terms of fuel cell power output in our experiment. The bare Ag cathode completely agglomerated into islands during fuel cell operation at 450 °C, while the ALD CeO(x) treatment effectively protects the porosity of the cathode. We also discuss the long-term stability of ALD CeO(x)-treated Ag cathodes related to the microstructure of the layers. PMID:27008979

  2. Nanoporous silver cathode surface treated by atomic layer deposition of CeO x for low-temperature solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Chean Neoh, Ke; Han, Gwon Deok; Kim, Manjin; Kim, Jun Woo; Jong Choi, Hyung; Park, Suk Won; Shim, Joon Hyung

    2016-05-01

    We evaluated the performance of solid oxide fuel cells (SOFCs) with a 50 nm thin silver (Ag) cathode surface treated with cerium oxide (CeO x ) by atomic layer deposition (ALD). The performances of bare and ALD-treated Ag cathodes were evaluated on gadolinia-doped ceria (GDC) electrolyte supporting cells with a platinum (Pt) anode over 300 °C-450 °C. Our work confirms that ALD CeO x treatment enhances cathodic performance and thermal stability of the Ag cathode. The performance difference between cells using a Ag cathode optimally treated with an ALD CeO x surface and a reference Pt cathode is about 50% at 450 °C in terms of fuel cell power output in our experiment. The bare Ag cathode completely agglomerated into islands during fuel cell operation at 450 °C, while the ALD CeO x treatment effectively protects the porosity of the cathode. We also discuss the long-term stability of ALD CeO x -treated Ag cathodes related to the microstructure of the layers.

  3. DEVELOPMENT OF SUPERIOR ENTRAINMENT SEPARATORS

    EPA Science Inventory

    An experimental and theoretical program was carried out to develop an improved design for entrainment separators for scrubbers. The problems of separation efficiency, suspended solids deposition and plugging of the entrainment separator were of primary concern. A pilot scale entr...

  4. Effects of annealing process on magnetic properties and structures of Nd-Pr-Ce-Fe-B melt-spun powders

    NASA Astrophysics Data System (ADS)

    Pei, Kun; Lin, Min; Yan, Aru; Zhang, Xing

    2016-05-01

    The effects of annealing process on magnetic properties and structures of Nd-Pr-Ce-Fe-B melt-spun powders have been investigated. The magnetic properties improve a lot when the annealing temperature is 590-650 °C and the annealing time exceeds 1 min. The magnetic properties is stable when the annealing time is 590-650 °C. The powders contains obvious grains when the annealing time is only 1 min, while the grains grow up obviously, leading to the decrease of Br and (BH)max, when the annealing time is more than 9 min. The Hcj changes little for different annealing time. The cooling rate also affects the magnetic properties of powders with different Ce-content. Faster cooling rate is favorable to improve magnetic properties with low Ce-content powders, while high Ce-content powders need slower cooling rate.

  5. Digital processing of signals from LaBr3:Ce scintillation detectors

    NASA Astrophysics Data System (ADS)

    Nakhostin, M.; Podolyak, Zs; Regan, P. H.

    2014-12-01

    In this paper, we report on the results of digital signal processing of LaBr3(Ce) detectors. The photomultiplier (PMT) output signals from two cylindrical LaBr3(Ce) detectors (1.5'' diameter and 2'' tall) were directly digitized with an ultrafast digitizer (sampling rate up to 4 GSample/s and 10-bits resolution) and the energy and timing information were extracted through offline analysis of the pulses. It is shown that at high sampling rates (4 GS/s) a simple integration of pulses is sufficient to reproduce the analogue energy resolution of the detectors (3.5% at 662 keV energy) and by employing a digital version of constant-fraction discrimination (CFD) timing a time resolution of 240 ps (FWHM) is achieved at the energy lines of 60Co. The effects of pulse sampling rate were studied, indicating a degradation of the performance of the detectors with reducing the pulse sampling rate. In particular, it was found that at sampling rates below 1 GS/s, the digital timing can be limited by the aliasing error. By using an anti-aliasing filter, a time resolution of 375 ps (FWHM) and an energy resolution of 3.5% at 662 keV were achieved with a sampling rate of 500 MS/s.

  6. The effects of physicochemical properties of CeO2 nanoparticles on toxicity to soil denitrification processes

    NASA Astrophysics Data System (ADS)

    Dahle, Jessica Teague

    The studies presented in this thesis identify the impact of NP CeO 2 on soil denitrifying microbial communities and reveal that physical and chemical characteristics including particle size, speciation, concentration, pH, and presence of ligands are key to predicting environmental fate and reactivity of NP CeO2 in the soil. A review of the literature in Chapter 1 revealed a widespread lack of toxicological information for soil exposures to NP CeO2. Soil denitrifying bacteria are a keystone species because they serve an important role in the global nitrogen cycle controlling the atmospheric nitrogen input. Soil denitrifiers are important to this study because the reducing conditions during denitrification could induce phase transformation of Ce(IV) to Ce(III), potentially influencing the toxicity of Ce. Cerium is well known for being the only lanthanide that is thermodynamically stable in both the trivalent and tetravalent state in low temperature geochemical environments. Using well characterized NP Ce(IV)O 2 as well as bulk soluble Ce(III), batch denitrification experiments were conducted to evaluate the toxicity of Ce species to the denitrifying community in a Toccoa sandy loam soil. The statistical analysis on the antimicrobial effect on soil denitrifiers was conducted using both steady-state evaluation and zero-order kinetic models in order to compare the toxicity of the Ce(III) species to the NPs. These studies, presented in Chapter 3, show that soluble Ce(III) is far more toxic than Ce(IV)O2 NPs when an equal total concentration of Ce is used, though both species exhibit toxicity to the denitrifiers via statistically significant inhibition of soil denitrification processes. Particle-size dependent toxicity, species-dependent toxicity, and concentration-dependent toxicity were all observed in this study for both the steady-state and the kinetic evaluations. The possibility of toxicity enhancement and diminishment via dissolution and ligand complexation

  7. Ionic Conduction and Fuel Cell Performance of Ba0.97Ce0.8Ho0.2O3-α Ceramic

    NASA Astrophysics Data System (ADS)

    Qiu, Li-gan

    2006-08-01

    The perovskite-type-oxide solid solution Ba0.97Ce0.8Ho0.2O3-α was prepared by high temperature solid-state reaction and its single-phase character was confirmed by X-ray diffraction. The ionic conduction of the sample was investigated using electrical methods at elevated temperatures, and the performance of the hydrogen-air fuel cell using the sample as solid electrolyte was measured, which were compared with those of BaCe0.8Ho0.2O3-α. In wet hydrogen, BaCe0.8Ho0.2O3-α almost exhibits pure protonic conduction at 600-1000 °C, and its protonic transport number is 1 at 600-900 °C and 0.99 at 1000 °C. Similarly, Ba0.97Ce0.8Ho0.2O3-α exhibits pure protonic conduction with the protonic transport number of 1 at 600-700 °C, but its protonic conduction is slightly lower than that of BaCe0.8Ho0.2O3-α, and the protonic transport number are 0.99-0.96 at 800-1000 °C. In wet air, the two samples both show low protonic and oxide ionic conduction. For Ba0.97Ce0.8Ho0.2O3-α, the protonic and oxide ionic transport numbers are 0.01-0.11 and 0.30-0.31 respectively, and for BaCe0.8Ho0.2O3-α, 0.01-0.09 and 0.27-0.33 respectively. Ionic conductivities of Ba0.97Ce0.8Ho0.2O3-α are higher than those of BaCe0.8Ho0.2O3-α under wet hydrogen and wet air. The performance of the fuel cell using Ba0.97Ce0.8Ho0.2O3-α as solid electrolyte is better than that of BaCe0.8Ho0.2O3-α. At 1000 °C, its maximum short-circuit current density and power output density are 465 mA/cm2 and 112 mW/cm2, respectively.

  8. Distributed generation - the fuel processing example

    SciTech Connect

    Victor, R.A.; Farris, P.J.; Maston, V.

    1996-12-31

    The increased costs of transportation and distribution are leading many commercial and industrial firms to consider the on-site generation for energy and other commodities used in their facilities. This trend has been accelerated by the development of compact, efficient processes for converting basic raw materials into finished services at the distributed sites. Distributed generation with the PC25{trademark} fuel cell power plant is providing a new cost effective technology to meet building electric and thermal needs. Small compact on-site separator systems are providing nitrogen and oxygen to many industrial users of these gases. The adaptation of the fuel processing section of the PC25 power plant for on-site hydrogen generation at industrial sites extends distributed generation benefits to the users of industrial hydrogen.

  9. Data processing and initial results from the CE-3 Extreme Ultraviolet Camera

    NASA Astrophysics Data System (ADS)

    Feng, Jian-Qing; Liu, Jian-Jun; He, Fei; Yan, Wei; Ren, Xin; Tan, Xu; He, Ling-Ping; Chen, Bo; Zuo, Wei; Wen, Wei-Bin; Su, Yan; Zou, Yong-Liao; Li, Chun-Lai

    2014-12-01

    The Extreme Ultraviolet Camera (EUVC) onboard the Chang'e-3 (CE-3) lander is used to observe the structure and dynamics of Earth's plasmasphere from the Moon. By detecting the resonance line emission of helium ions (He+) at 30.4 nm, the EUVC images the entire plasmasphere with a time resolution of 10 min and a spatial resolution of about 0.1 Earth radius (RE) in a single frame. We first present details about the data processing from EUVC and the data acquisition in the commissioning phase, and then report some initial results, which reflect the basic features of the plasmasphere well. The photon count and emission intensity of EUVC are consistent with previous observations and models, which indicate that the EUVC works normally and can provide high quality data for future studies.

  10. Complete Oxidation of Benzene Over CuO-CeO2 Catalysts Prepared Using Different Process.

    PubMed

    Jung, Won Young; Hong, Seong-Soo

    2016-05-01

    Catalytic combustion of benzene over CuO-CeO2 mixed oxides has been investigated. The CuO-CeO2 mixed oxides were prepared using various methods and characterized by XRD, BET and TPR. For the CuO-CeO2 catalysts with a Cu/(Cu + Ce) molar ratio of more than 0.5, highly dispersed copper oxide species were shown at 2θ = 35.5 degrees and 38.8 degrees. The CuO-CeO2 catalyst prepared using co-precipitation method showed the highest activity. In addition, the highest activity is shown on Cu0.35 (the index denotes the molar ratio Cu/(Cu + Ce)) sample and then it decreases on Cu0.5 and Cu0.6 samples. PMID:27483793

  11. Mesler entrainment in alcohols

    NASA Astrophysics Data System (ADS)

    Saylor, J. R.; Sundberg, R. K.

    2012-11-01

    When a drop impacts a flat surface of the same liquid at an intermediate velocity, the impact can result in the formation of a very large number of very small bubbles. At lower velocities, drops bounce or float, and at larger velocities a single bubble forms, or there is a splash. The formation of large numbers of small bubbles during intermediate velocity impacts is termed Mesler entrainment and its controlling mechanism is poorly understood. Existing research has shown that Mesler entrainment is highly irreproducible when water is the working fluid, and very reproducible when silicone oil is the working fluid. Whether this is because water is problematic, or silicone oil is uniquely well-suited, is unclear. To answer this question, experiments were conducted using three different alcohols. The results of these experiments were very reproducible for all alcohols tested, suggesting that there is something unique about water which accounts for its lack of reproducibility. The data from these experiments were also used to develop a dimensionless group that quantifies the conditions under which Mesler entrainment occurs. This dimensionless group is used to provide insight into the mechanism of this unique method of bubble formation.

  12. MEASUREMENT OF ENTRAINED ORGANIC DROPLET SIZES AND TOTAL CONCENTRATION FOR AQUEOUS STREAMS FROM THE CAUSTIC-SIDE SOLVENT EXTRACTION PROCESS

    SciTech Connect

    Nash, C; Samuel Fink, S; Michael Restivo, M; Dan Burns, D; Wallace Smith, W; S Crump, S; Zane Nelson, Z; Thomas Peters, T; Fernando Fondeur, F; Michael Norato, M

    2007-02-01

    The Modular Caustic-Side Solvent Extraction Unit (MCU) and the Salt Waste Processing Facility will remove radioactive cesium from Savannah River Site supernate wastes using an organic solvent system. Both designs include decanters and coalescers to reduce carryover of organic solvent droplets. Savannah River National Laboratory personnel conducted experimental demonstrations using a series of four 2-cm centrifugal contactors. They also examined organic carryover during operation of a CINC (Costner Industries Nevada Corporation) V-5 contactor under prototypical conditions covering the range of expected MCU operation. This report details the findings from those studies and the implications on design for the MCU.

  13. Modeling of a CeO2 thermochemistry reduction process for hydrogen production by solar concentrated energy

    NASA Astrophysics Data System (ADS)

    Valle-Hernández, Julio; Romero-Paredes, Hernando; Arancibia-Bulnes, Camilo A.; Villafan-Vidales, Heidi I.; Espinosa-Paredes, Gilberto

    2016-05-01

    In this paper the simulation of the thermal reduction for hydrogen production through the decomposition of cerium oxide is presented. The thermochemical cycle for hydrogen production consists of the endothermic reduction of CeO2 at high temperature, where concentrated solar energy is used as a source of heat; and of the subsequent steam hydrolysis of the resulting cerium oxide to produce hydrogen. For the thermochemical process, a solar reactor prototype is proposed; consisting of a cubic receptacle made of graphite fiber thermally insulated. Inside the reactor a pyramidal arrangement with nine tungsten pipes is housed. The pyramidal arrangement is made respect to the focal point where the reflected energy is concentrated. The solar energy is concentrated through the solar furnace of high radiative flux. The endothermic step is the reduction of the cerium oxide to lower-valence cerium oxide, at very high temperature. The exothermic step is the hydrolysis of the cerium oxide (III) to form H2 and the corresponding initial cerium oxide made at lower temperature inside the solar reactor. For the modeling, three sections of the pipe where the reaction occurs were considered; the carrier gas inlet, the porous medium and the reaction products outlet. The mathematical model describes the fluid mechanics; mass and energy transfer occurring therein inside the tungsten pipe. Thermochemical process model was simulated in CFD. The results show a temperature distribution in the solar reaction pipe and allow obtaining the fluid dynamics and the heat transfer within the pipe. This work is part of the project "Solar Fuels and Industrial Processes" from the Mexican Center for Innovation in Solar Energy (CEMIE-Sol).

  14. Pyroprocess for processing spent nuclear fuel

    DOEpatents

    Miller, William E.; Tomczuk, Zygmunt

    2002-01-01

    This is a pyroprocess for processing spent nuclear fuel. The spent nuclear fuel is chopped into pieces and placed in a basket which is lowered in to a liquid salt solution. The salt is rich in ZrF.sub.4 and containing alkali or alkaline earth fluorides, and in particular, the salt chosen was LiF-50 mol % ZrF.sub.4 with a eutectic melting point of 500.degree. C. Prior to lowering the basket, the salt is heated to a temperature of between 550.degree. C. and 700.degree. C. in order to obtain a molten solution. After dissolution the oxides of U, Th, rare earth and other like oxides, the salt bath solution is subject to hydro-fluorination to remove the oxygen and then to a fluorination step to remove U as gaseous UF.sub.6. In addition, after dissolution, the basket contains PuO.sub.2 and undissolved parts of the fuel rods, and the basket and its contents are processed to remove the Pu.

  15. Cellular processing of copper-67-labeled monoclonal antibody chCE7 by human neuroblastoma cells.

    PubMed

    Novak-Hofer, I; Amstutz, H P; Mäcke, H R; Schwarzbach, R; Zimmermann, K; Morgenthaler, J J; Schubiger, P A

    1995-01-01

    Monoclonal antibody chCE7, an internalizing neuroblastoma-specific chimeric antibody, was derivatized with the macrocyclic amine ligand 4-[(1,4,8,11-tetraazacyclotetradec-1-yl)-methyl] benzoic acid tetrahydrochloride and labeled with the potential therapeutic nuclide 67Cu. Using pulse labeling and an acid elution endocytosis assay, 67Cu-chCE7 was found to be internalized into human neuroblastoma (SKN-AS) cells at a similar rate and to a similar extent as 125I-labeled chCE7. Uptake of 67Cu-chCE7 and 125I-chCE7 into the acid stable (intracellular) pool proceeded with similar kinetics during the first 2 h of internalization. However, in contrast to 125I-chCE7-loaded cells, at later times intracellular radioactivity kept increasing in the case of 67Cu-chCE7-loaded cells. It was shown that this effect is due to the intracellular accumulation of a low M(r) degradation product consisting of the 67Cu-4[(1,4,8,11-tetraazacyclotetradec-1-yl)-methyl] benzoic acid complex, possibly with a short peptide attached to it. Degradation of both 125I-chCE7 and 67Cu-chCE7 was inhibited by chloroquine, indicating endosomal or lysosomal degradation, and a 43,000 M(r) fragment was found to be the major high M(r) degradation product in both cases. Although at times between 4 and 6 h of internalization intracellular breakdown of 67Cu-chCE7 was found to proceed more slowly, the major difference between the two immunoconjugates resides in the prolonged cellular retention of the 67Cu-chCE7 metabolite. PMID:7805039

  16. Y0.08Sr0.88TiO3-CeO2 composite as a diffusion barrier layer for stainless-steel supported solid oxide fuel cell

    NASA Astrophysics Data System (ADS)

    Kim, Kun Joong; Kim, Sun Jae; Choi, Gyeong Man

    2016-03-01

    A new diffusion barrier layer (DBL) is proposed for solid oxide fuel cells (SOFCs) supported on stainless-steel where DBL prevents inter-diffusion of atoms between anode and stainless steel (STS) support during fabrication and operation of STS-supported SOFCs. Half cells consisting of dense yttria-stabilized zirconia (YSZ) electrolyte, porous Ni-YSZ anode layer, and ferritic STS support, with or without Y0.08Sr0.88TiO3-CeO2 (YST-CeO2) composite DBL, are prepared by tape casting and co-firing at 1250 and 1350 °C, respectively, in reducing (H2) atmosphere. The porous YST-CeO2 layer (t ∼ 60 μm) blocks inter-diffusion of Fe and Ni, and captures the evaporated Cr during cell fabrication (1350 °C). The cell with DBL and La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF) cathode achieved a maximum power density of ∼220 mW cm-2 which is stable at 700 °C. In order to further improve the power performance, Ni coarsening in anode during co-firing must be prevented or alternative anode which is resistive to coarsening is suggested. This study demonstrates that the new YST-CeO2 layer is a promising as a DBL for stainless-steel-supported SOFCs fabricated with co-firing process.

  17. Situ process for making multifunctional fuel additives

    SciTech Connect

    Carrier, R.C.; Allen, B.R.

    1984-02-28

    Disclosed is an in situ or ''one pot'' process for making a fuel additive comprising reacting an excess of at least one N-primary alkylalkylene diamine with maleic anhydride in the presence of from 20 to 36 weight percent of a mineral oil reaction diluent at a temperature ranging from ambient to about 225/sup 0/ F. and recovering a product containing a primary aliphatic hydrocarbon amino alkylene substituted asparagine, an N-primary alkylalkylene diamine in the reaction oil with the product having a by-product succinimide content not in excess of 1.0 weight percent, based on the weight of asparagine present.

  18. Insight into the structure and functional application of the Sr0.95Ce0.05CoO3-δ cathode for solid oxide fuel cells.

    PubMed

    Yang, Wei; Zhang, Huairuo; Sun, Chunwen; Liu, Lilu; Alonso, J A; Fernández-Díaz, M T; Chen, Liquan

    2015-04-01

    A new perovskite cathode, Sr0.95Ce0.05CoO3-δ, performs well for oxygen-reduction reactions in solid oxide fuel cells (SOFCs). We gain insight into the crystal structure of Sr1-xCexCoO3-δ (x = 0.05, 0.1) and temperature-dependent structural evolution of Sr0.95Ce0.05CoO3-δ by X-ray diffraction, neutron powder diffraction, and scanning transmission electron microscopy experiments. Sr0.9Ce0.1CoO3-δ shows a perfectly cubic structure (a = a0), with a large oxygen deficiency in a single oxygen site; however, Sr0.95Ce0.05CoO3-δ exhibits a tetragonal perovskite superstructure with a double c axis, defined in the P4/mmm space group, that contains two crystallographically different cobalt positions, with distinct oxygen environments. The structural evolution of Sr0.95Ce0.05CoO3-δ at high temperatures was further studied by in situ temperature-dependent NPD experiments. At 1100 K, the oxygen atoms in Sr0.95Ce0.05CoO3-δ show large and highly anisotropic displacement factors, suggesting a significant ionic mobility. The test cell with a La0.8Sr0.2Ga0.83Mg0.17O3-δ-electrolyte-supported (∼300 μm thickness) configuration yields peak power densities of 0.25 and 0.48 W cm(-2) at temperatures of 1023 and 1073 K, respectively, with pure H2 as the fuel and ambient air as the oxidant. The electrochemical impedance spectra evolution with time of the symmetric cathode fuel cell measured at 1073 K shows that the Sr0.95Ce0.05CoO3-δ cathode possesses superior ORR catalytic activity and long-term stability. Mixed ionic-electronic conduction properties of Sr0.95Ce0.05CoO3-δ account for its good performance as an oxygen-reduction catalyst. PMID:25756843

  19. Catalytic oxidation with Al-Ce-Fe-PILC as a post-treatment system for coffee wet processing wastewater.

    PubMed

    Sanabria, Nancy R; Peralta, Yury M; Montañez, Mardelly K; Rodríguez-Valencia, Nelson; Molina, Rafael; Moreno, Sonia

    2012-01-01

    The effluent from the anaerobic biological treatment of coffee wet processing wastewater (CWPW) contains a non-biodegradable compound that must be treated before it is discharged into a water source. In this paper, the wet hydrogen peroxide catalytic oxidation (WHPCO) process using Al-Ce-Fe-PILC catalysts was researched as a post-treatment system for CWPW and tested in a semi-batch reactor at atmospheric pressure and 25 °C. The Al-Ce-Fe-PILC achieved a high conversion rate of total phenolic compounds (70%) and mineralization to CO(2) (50%) after 5 h reaction time. The chemical oxygen demand (COD) of coffee processing wastewater after wet hydrogen peroxide catalytic oxidation was reduced in 66%. The combination of the two treatment methods, biological (developed by Cenicafé) and catalytic oxidation with Al-Ce-Fe-PILC, achieved a 97% reduction of COD in CWPW. Therefore, the WHPCO using Al-Ce-Fe-PILC catalysts is a viable alternative for the post-treatment of coffee processing wastewater. PMID:22907449

  20. In Situ fuel processing in a microbial fuel cell.

    PubMed

    Bahartan, Karnit; Amir, Liron; Israel, Alvaro; Lichtenstein, Rachel G; Alfonta, Lital

    2012-09-01

    A microbial fuel cell (MFC) was designed in which fuel is generated in the cell by the enzyme glucoamylase, which is displayed on the surface of yeast. The enzyme digests starch specifically into monomeric glucose units and as a consequence enables further glucose oxidation by microorganisms present in the MFC anode. The oxidative enzyme glucose oxidase was coupled to the glucoamylase digestive enzyme. When both enzymes were displayed on the surface of yeast cells in a mixed culture, superior fuel-cell performance was observed in comparison with other combinations of yeast cells, unmodified yeast, or pure enzymes. The feasibility of the use of the green macroalgae Ulva lactuca in such a genetically modified MFC was also demonstrated. Herein, we report the performance of such fuel cells as a proof of concept for the enzymatic digestion of complex organic fuels in the anode of MFCs to render the fuel more available to microorganisms. PMID:22833422

  1. Entrainment and mixing mechanism in monsoon clouds

    NASA Astrophysics Data System (ADS)

    Bera, Sudarsan; Prabhakaran, Thara; Pandithurai, Govindan; Brenguier, Jean-Louis

    2015-04-01

    Entrainment and consequent mixing impacts the cloud microphysical parameters and droplet size distribution (DSD) significantly which are very important for cloud radiative properties and the mechanism for first rain drop formation. The entrainment and mixing mechanisms are investigated in this study using in situ observations in warm cumulus clouds over monsoon region. Entrainment is discussed in the framework of the homogeneous and inhomogeneous mixing concepts and their effects on cloud droplet size distribution, number concentration, liquid water content and mean radius are described. The degree of homogeneity increases with droplet number concentration and adiabatic fraction, indicating homogeneous type mixing in the cloud core where dilution is less. Inhomogeneous mixing is found to be a dominating process at cloud edges where dilution is significant. Cloud droplet size distribution (DSD) is found to shift towards lower sizes during a homogeneous mixing event in the cloud core whereas spectral width of DSD decreases due to inhomogeneous mixing at cloud edges. Droplet size spectra suggests that largest droplets are mainly formed in the less diluted cloud core while diluted cloud edges have relatively smaller droplets, so that raindrop formation occurs mainly in the core of the cloud. The origin of the entrained parcels in deep cumulus clouds is investigated using conservative thermodynamical parameters. The entrained parcels originate from a level close to the observation level or slightly below through lateral edges. Cloud edges are significantly diluted due to entrainment of sub-saturated environmental air which can penetrate several hundred meters inside the cloud before it gets mixed completely with the cloud mass. Less diluted parcels inside the cloud core originates from a level much below the cloud base height. Penetrating downdraft from cloud top is seldom observed at the observation level and strong downdrafts may be attributed to in-cloud oscillation

  2. Stratocumulus cloud deepening through entrainment

    NASA Technical Reports Server (NTRS)

    Randall, D. A.

    1984-01-01

    Under a substantial range of realistic conditions, stratocumulus cloud top entrainment is noted to either deepen an existing cloud layer or produce clouds in an unsaturated mixed layer, though the entrained air is warmer and drier than the mixed-layer air. These results, which apply irrespective of entrainment rate-determining mechanism, imply that the cloud top entrainment instability discussed by Randall (1980) and Deardorff (1980) does not necessarily destroy a layer cloud. Examples are given which include soundings, marine layer data, and simulation results produced by the UCLA general circulation model.

  3. Alternative fuels utilization and the automotive emission certification process

    SciTech Connect

    Not Available

    1980-03-01

    The Clean Air Act of 1977 requires that commercially offered automotive fuels and fuel additives be substantially similar to fuels used in certifying model year 1975 and later vehicles. Procedures for certifying that vehicles perform with emissions that meet the Clean Air Act specifications and the impact of this emissions certification process on the use of alternative fuels, such as alcohols, alcohol-gasoline blends and synthetic fuels, in highway vehicles is discussed. (LCL)

  4. Flowerlike CeO2 microspheres coated with Sr2Fe1.5Mo0.5Ox nanoparticles for an advanced fuel cell

    NASA Astrophysics Data System (ADS)

    Liu, Yanyan; Tang, Yongfu; Ma, Zhaohui; Singh, Manish; He, Yunjuan; Dong, Wenjing; Sun, Chunwen; Zhu, Bin

    2015-07-01

    Flowerlike CeO2 coated with Sr2Fe1.5Mo0.5Ox (Sr-Fe-Mo-oxide) nanoparticles exhibits enhanced conductivity at low temperatures (300-600 oC), e.g. 0.12 S cm-1 at 600 oC, this is comparable to pure ceria (0.1 S cm-1 at 800 oC). Advanced single layer fuel cell was constructed using the flowerlike CeO2/Sr-Fe-Mo-oxide layer attached to a Ni-foam layer coated with the conducting transition metal oxide. Such fuel cell has yielded a peak power density of 802 mWcm-2 at 550 oC. The mechanism of enhanced conductivity and cell performance were analyzed. These results provide a promising strategy for developing advanced low-temperature SOFCs.

  5. Flowerlike CeO2 microspheres coated with Sr2Fe1.5Mo0.5Ox nanoparticles for an advanced fuel cell

    PubMed Central

    Liu, Yanyan; Tang, Yongfu; Ma, Zhaohui; Singh, Manish; He, Yunjuan; Dong, Wenjing; Sun, Chunwen; Zhu, Bin

    2015-01-01

    Flowerlike CeO2 coated with Sr2Fe1.5Mo0.5Ox (Sr-Fe-Mo-oxide) nanoparticles exhibits enhanced conductivity at low temperatures (300–600 oC), e.g. 0.12 S cm−1 at 600 oC, this is comparable to pure ceria (0.1 S cm−1 at 800 oC). Advanced single layer fuel cell was constructed using the flowerlike CeO2/Sr-Fe-Mo-oxide layer attached to a Ni-foam layer coated with the conducting transition metal oxide. Such fuel cell has yielded a peak power density of 802 mWcm−2 at 550 oC. The mechanism of enhanced conductivity and cell performance were analyzed. These results provide a promising strategy for developing advanced low-temperature SOFCs. PMID:26154917

  6. Process for the production and recovery of fuel values from coal

    DOEpatents

    Sass, Allan; McCarthy, Harry E.; Kaufman, Paul R.; Finney, Clement S.

    1982-01-01

    A method of pyrolyzing and desulfurizing coal in a transport reactor to recover volatile fuel values and hydrogen by heating particulate coal entrained in a carrier gas substantially free of oxygen to a pyrolysis temperature in a zone within three seconds.

  7. Can cloud-top entrainment promote cloud growth?

    NASA Technical Reports Server (NTRS)

    Randall, D. A.

    1984-01-01

    The primary significance of Cloud Deepening through Entrainment (CDE) is that it can prevent the cloud top entrainment instability from destroying a cloud deck. Without suppressing the instability, CDE transforms it from a cloud destroyer to a cloud builder. The analysis does not depend on an entrainment hypothesis. Moreover, it is not restricted to PBL stratocumulus sheets. Stratiform clouds in the free atmosphere can be subject to CDE we need only reinterpret Ps as the pressure at the base of an elevated turbulent mixed layer. Modest departures from well mixedness will alter the results quantitatively but not qualitatively. Processes other than entrainment, such as surface evaporation, radiative cooling, and advection will often work with CDE to build a cloud layer; but of course they can also oppose CDE by reducing the relative humidity. If we make the weak assumption that the deepening of a cloud layer favors an increase in the cloud top entrainment rate (without specifying any particular functional relationship) we are led to speculate that CDE can cause runaway cloud growth, even in the absence of cloud top entrainment instability. through CDE entrainment leads to a deeper cloud, which leads to stronger entrainment.

  8. Evaluation of gasification and gas-cleanup processes for use in molten-carbonate fuel-cell power plants

    SciTech Connect

    Vidt, E.J.; Jablonski, G.; Alvin, M.A.; Wenglarz, R.A.; Patel, P.

    1981-12-01

    This interim report satisfies the Task B requirement to define process configurations for systems suitable for supplying fuel to molten carbonate fuel cells (MCFC) in industrial and utility power plants. The configurations studied include entrained, fluidized-bed, gravitating-bed, and molten salt gasifiers, both air and oxygen blown. Desulfurization systems utilizing wet scrubbing processes, such as Selexol and Rectisol II, and dry sorbents, such as iron oxide and dolomite, were chosen for evaluation. Cleanup systems not chosen by DOE's MCFC contractors, General Electric and United Technologies, Inc., for their MCFC power plant work by virtue of the resource requirements of those systems for commercial development were chosen for detailed study in Tasks C and D of this contract. Such systems include Westinghouse fluidized-bed gasification, air and oxygen blown, Rockwell molten carbonate air-blown gasification, METC iron oxide desulfurization, and dolomitic desulfurization. In addition, for comparison, gasification systems such as the Texaco entrained and the British Gas/Lurgi slagging units, along with wet scrubbing by Rectisol II, have also been chosen for detailed study.

  9. MONOLITHIC FUEL FABRICATION PROCESS DEVELOPMENT AT THE IDAHO NATIONAL LABORATORY_

    SciTech Connect

    G. A. Moore; F. J. Rice; N. E. Woolstenhulme; J-F. Jue; B. H. Park; S. E. Steffler; N. P. Hallinan; M. D. Chapple; M. C. Marshall; B. L. Mackowiak; C. R. Clark; B. H. Rabin

    2009-11-01

    Full-size/prototypic U10Mo monolithic fuel-foils and aluminum clad fuel plates are being developed at the Idaho National Laboratory’s (INL) Materials and Fuels Complex (MFC). These efforts are focused on realizing Low Enriched Uranium (LEU) high density monolithic fuel plates for use in High Performance Research and Test Reactors. The U10Mo fuel foils under development afford a fuel meat density of ~16 gU/cc and thus have the potential to facilitate LEU conversions without any significant reactor-performance penalty. An overview is provided of the ongoing monolithic UMo fuel development effort, including application of a zirconium barrier layer on fuel foils, fabrication scale-up efforts, and development of complex/graded fuel foils. Fuel plate clad bonding processes to be discussed include: Hot Isostatic Pressing (HIP) and Friction Bonding (FB).

  10. MONOLITHIC FUEL FABRICATION PROCESS DEVELOPMENT AT THE IDAHO NATIONAL LABORATORY

    SciTech Connect

    Glenn A. Moore; Francine J. Rice; Nicolas E. Woolstenhulme; W. David SwanK; DeLon C. Haggard; Jan-Fong Jue; Blair H. Park; Steven E. Steffler; N. Pat Hallinan; Michael D. Chapple; Douglas E. Burkes

    2008-10-01

    Within the Reduced Enrichment for Research and Test Reactors (RERTR) program directed by the US Department of Energy (DOE), UMo fuel-foils are being developed in an effort to realize high density monolithic fuel plates for use in high-flux research and test reactors. Namely, targeted are reactors that are not amenable to Low Enriched Uranium (LEU) fuel conversion via utilization of high density dispersion-based fuels, i.e. 8-9 gU/cc. LEU conversion of reactors having a need for >8-9 gU/cc fuel density will only be possible by way of monolithic fuel forms. The UMo fuel foils under development afford fuel meat density of ~16 gU/cc and thus have the potential to facilitate LEU conversions without any significant reactor-performance penalty. Two primary challenges have been established with respect to UMo monolithic fuel development; namely, fuel element fabrication and in-reactor fuel element performance. Both issues are being addressed concurrently at the Idaho National Laboratory. An overview is provided of the ongoing monolithic UMo fuel development effort at the Idaho National Laboratory (INL); including development of complex/graded fuel foils. Fabrication processes to be discussed include: UMo alloying and casting, foil fabrication via hot rolling, fuel-clad interlayer application via co-rolling and thermal spray processes, clad bonding via Hot Isostatic Pressing (HIP) and Friction Bonding (FB), and fuel plate finishing.

  11. Power plant intake entrainment analysis

    SciTech Connect

    Edinger, J.E.; Kolluru, V.S.

    2000-04-01

    Power plant condenser cooling water intake entrainment of fish eggs and larvae is becoming an issue in evaluating environmental impacts around the plants. Methods are required to evaluate intake entrainment on different types of water bodies. Presented in this paper is a derivation of the basic relationships for evaluating entrainment from the standing crop of fish eggs and larvae for different regions of a water body, and evaluating the rate of entrainment from the standing crop. These relationships are coupled with a 3D hydrodynamic and transport model that provides the currents and flows required to complete the entrainment evaluation. Case examples are presented for a simple river system, and for the more complex Delaware River Estuary with multiple intakes. Example evaluations are made for individual intakes, and for the cumulative impacts of multiple intakes.

  12. The entraining moist boundary layer

    NASA Technical Reports Server (NTRS)

    Randall, D. A.

    1978-01-01

    A unified theory of entrainment into the planetary boundary layer is presented. It is assumed that the rates of buoyant and shear production of turbulence kinetic energy can be determined in terms of the entrainment mass flux. An expression is derived from the conservation law for turbulence kinetic energy, which, with the introduction of an empirical parameter, can be used together with a second relation between turbulence kinetic energy and the turbulence velocity scale to obtain the mass entrainment flux. The theory provides descriptions of storage-limited entrainment, buoyancy-limited entrainment into a clear mixed layer, and shallowing. It has been incorporated into a simulation of Day 33 of the Wangara experiment using a simple mixed layer model.

  13. Single-step process to prepare CeO2 nanotubes with improved catalytic activity.

    PubMed

    González-Rovira, Leandro; Sánchez-Amaya, José M; López-Haro, Miguel; del Rio, Eloy; Hungría, Ana B; Midgley, Paul; Calvino, José J; Bernal, Serafín; Botana, F Javier

    2009-04-01

    CeO(2) nanotubes have been grown electrochemically using a porous alumina membrane as a template. The resulting material has been characterized by means of scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy, high-angle annular dark-field scanning transmission electron microscopy tomography, high-resolution electron microscopy (HREM), and electron energy loss spectroscopy. According to SEM, the outer diameter of the nanotubes corresponds to the pore size (200 nm) of the alumina membrane, and their length ranges between 30 and 40 microm. HREM images have revealed that the width of the nanotube walls is about 6 nm. The catalytic activity of these novel materials for the CO oxidation reaction is compared to that of a polycrystalline powder CeO(2) sample prepared by a conventional route. The activity of the CeO(2) nanotubes is shown to be in the order of 400 times higher per gram of oxide at 200 degrees C (77.2 x 10(-2) cm(3) CO(2) (STP)/(gxs) for the nanotube-shaped CeO(2) and 0.16 x 10(-2) cm(3) CO(2) (STP)/(gxs) for the powder CeO(2)). PMID:19245236

  14. Overview of fuel processing options for polymer electrolyte fuel cell systems

    SciTech Connect

    Kumar, R.

    1995-12-31

    The polymer electrolyte fuel cell (PEFC) is being developed for use in heavy- and light-duty transportation applications. While this fuel cell has been used successfully in buses and vans with compressed hydrogen as the on-board fuel [1,2], the fuel cell system must incorporate fuel processing (reforming) for any other on-board fuel to produce the hydrogen or hydrogen-rich fuel gas to be fed to the fuel cell stack. This is true even for alternative methods of storing hydrogen, such as use of a metal hydride or liquefied hydrogen. The ``fuel processing`` needed to recover the hydrogen includes providing the heat of dissociation of the hydride and cooling the hydrogen to the temperature of the fuel cell stack. Discussed below are some of the options being considered for processing of on-board fuels (other than compressed hydrogen) to generate the fuel cell anode gas, and the effects of fuel processing on system design, efficiency, steady-state and dynamic performance, and other factors.

  15. Photodynamic Processes and Lasing in Ce,Yb:LiYXLu1-XF4 Crystals

    NASA Astrophysics Data System (ADS)

    Nurtdinova, L. A.

    2015-09-01

    Measurements of photoconductivity were conducted in LiYXLu1-XF4:RE (RE = Ce(1%), Yb (1%); x = 0..1) crystals. It was found that the excited state absorption transitions of Ce3+ ions are intracenter and terminate at 6s state of cerium ions. Lasing at room temperature was achieved, differential gain (up to ~22%) and tuning range were determined. By lowering the temperature of the active element and using additional antisolarant pumping at 532 nm lasing differential gain efficiency was increased (up to ~ 35%), and the tuning range was expanded.

  16. Process for producing fluid fuel from coal

    DOEpatents

    Hyde, Richard W.; Reber, Stephen A.; Schutte, August H.; Nadkarni, Ravindra M.

    1977-01-01

    Process for producing fluid fuel from coal. Moisture-free coal in particulate form is slurried with a hydrogen-donor solvent and the heated slurry is charged into a drum wherein the pressure is so regulated as to maintain a portion of the solvent in liquid form. During extraction of the hydrocarbons from the coal, additional solvent is added to agitate the drum mass and keep it up to temperature. Subsequently, the pressure is released to vaporize the solvent and at least a portion of the hydrocarbons extracted. The temperature of the mass in the drum is then raised under conditions required to crack the hydrocarbons in the drum and to produce, after subsequent stripping, a solid coke residue. The hydrocarbon products are removed and fractionated into several cuts, one of which is hydrotreated to form the required hydrogen-donor solvent while other fractions can be hydrotreated or hydrocracked to produce a synthetic crude product. The heaviest fraction can be used to produce ash-free coke especially adapted for hydrogen manufacture. The process can be made self-sufficient in hydrogen and furnishes as a by-product a solid carbonaceous material with a useful heating value.

  17. Gaseous Fuel Injection Modeling using a Gaseous Sphere Injection Methodology

    SciTech Connect

    Hessel, R P; Aceves, S M; Flowers, D L

    2006-03-06

    The growing interest in gaseous fuels (hydrogen and natural gas) for internal combustion engines calls for the development of computer models for simulation of gaseous fuel injection, air entrainment and the ensuing combustion. This paper introduces a new method for modeling the injection and air entrainment processes for gaseous fuels. The model uses a gaseous sphere injection methodology, similar to liquid droplet in injection techniques used for liquid fuel injection. In this paper, the model concept is introduced and model results are compared with correctly- and under-expanded experimental data.

  18. Speech Entrainment Compensates for Broca's Area Damage

    PubMed Central

    Fridriksson, Julius; Basilakos, Alexandra; Hickok, Gregory; Bonilha, Leonardo; Rorden, Chris

    2015-01-01

    Speech entrainment (SE), the online mimicking of an audiovisual speech model, has been shown to increase speech fluency in patients with Broca's aphasia. However, not all individuals with aphasia benefit from SE. The purpose of this study was to identify patterns of cortical damage that predict a positive response SE's fluency-inducing effects. Forty-four chronic patients with left hemisphere stroke (15 female) were included in this study. Participants completed two tasks: 1) spontaneous speech production, and 2) audiovisual SE. Number of different words per minute was calculated as a speech output measure for each task, with the difference between SE and spontaneous speech conditions yielding a measure of fluency improvement. Voxel-wise lesion-symptom mapping (VLSM) was used to relate the number of different words per minute for spontaneous speech, SE, and SE-related improvement to patterns of brain damage in order to predict lesion locations associated with the fluency-inducing response to speech entrainment. Individuals with Broca's aphasia demonstrated a significant increase in different words per minute during speech entrainment versus spontaneous speech. A similar pattern of improvement was not seen in patients with other types of aphasia. VLSM analysis revealed damage to the inferior frontal gyrus predicted this response. Results suggest that SE exerts its fluency-inducing effects by providing a surrogate target for speech production via internal monitoring processes. Clinically, these results add further support for the use of speech entrainment to improve speech production and may help select patients for speech entrainment treatment. PMID:25989443

  19. SAFEGUARDS EXPERIENCE ON THE DUPIC FUEL CYCLE PROCESS

    SciTech Connect

    J. HONG; H. KIM; ET AL

    2001-02-01

    Safeguards have been applied to the R and D process for directly fabricating CANDU fuel with PWR spent fuel material. Safeguards issues to be resolved were identified in the areas such as international cooperation on handling foreign origin nuclear material, technology development of operator's measurement system of the bulk handling process of spent fuel material, and a built-in C/S system for independent verification of material flow. The fuel cycle concept (Direct Use of PWR spent fuel in CANDU, DUPIC) was developed in consideration of reutilization of over-flowing spent fuel resources at PWR sites and a reduction of generated high level wastes. All those safeguards issues have been finally resolved, and the first batch of PWR spent fuel material was successfully introduced in the DUPIC lab facility and has been in use for routine process development.

  20. Fuel Cell Stations Automate Processes, Catalyst Testing

    NASA Technical Reports Server (NTRS)

    2010-01-01

    Glenn Research Center looks for ways to improve fuel cells, which are an important source of power for space missions, as well as the equipment used to test fuel cells. With Small Business Innovation Research (SBIR) awards from Glenn, Lynntech Inc., of College Station, Texas, addressed a major limitation of fuel cell testing equipment. Five years later, the company obtained a patent and provided the equipment to the commercial world. Now offered through TesSol Inc., of Battle Ground, Washington, the technology is used for fuel cell work, catalyst testing, sensor testing, gas blending, and other applications. It can be found at universities, national laboratories, and businesses around the world.

  1. Renewable hydrogen production for fossil fuel processing

    SciTech Connect

    Greenbaum, E.; Lee, J.W.; Tevault, C.V.

    1995-06-01

    In the fundamental biological process of photosynthesis, atmospheric carbon dioxide is reduced to carbohydrate using water as the source of electrons with simultaneous evolution of molecular oxygen: H{sub 2}O + CO{sub 2} + light {yields} O{sub 2} + (CH{sub 2}O). It is well established that two light reactions, Photosystems I and II (PSI and PSII) working in series, are required to perform oxygenic photosynthesis. Experimental data supporting the two-light reaction model are based on the quantum requirement for complete photosynthesis, spectroscopy, and direct biochemical analysis. Some algae also have the capability to evolve molecular hydrogen in a reaction energized by the light reactions of photosynthesis. This process, now known as biophotolysis, can use water as the electron donor and lead to simultaneous evolution of molecular hydrogen and oxygen. In green algae, hydrogen evolution requires prior incubation under anaerobic conditions. Atmospheric oxygen inhibits hydrogen evolution and also represses the synthesis of hydrogenase enzyme. CO{sub 2} fixation competes with proton reduction for electrons relased from the photosystems. Interest in biophotolysis arises from both the questions that it raises concerning photosynthesis and its potential practical application as a process for converting solar energy to a non-carbon-based fuel. Prior data supported the requirement for both Photosystem I and Photosystem II in spanning the energy gap necessary for biophotolysis of water to oxygen and hydrogen. In this paper we report the at PSII alone is capable of driving sustained simultaneous photoevolution of molecular hydrogen and oxygen in an anaerobically adapted PSI-deficient strain of Chlamydomonas reinhardtii, mutant B4, and that CO{sub 2} competes as an electron acceptor.

  2. Reactivity of atomically dispersed Pt(2+) species towards H2: model Pt-CeO2 fuel cell catalyst.

    PubMed

    Lykhach, Yaroslava; Figueroba, Alberto; Camellone, Matteo Farnesi; Neitzel, Armin; Skála, Tomáš; Negreiros, Fabio R; Vorokhta, Mykhailo; Tsud, Nataliya; Prince, Kevin C; Fabris, Stefano; Neyman, Konstantin M; Matolín, Vladimír; Libuda, Jörg

    2016-03-01

    The reactivity of atomically dispersed Pt(2+) species on the surface of nanostructured CeO2 films and the mechanism of H2 activation on these sites have been investigated by means of synchrotron radiation photoelectron spectroscopy and resonant photoemission spectroscopy in combination with density functional calculations. Isolated Pt(2+) sites are found to be inactive towards H2 dissociation due to high activation energy required for H-H bond scission. Trace amounts of metallic Pt are necessary to initiate H2 dissociation on Pt-CeO2 films. H2 dissociation triggers the reduction of Ce(4+) cations which, in turn, is coupled with the reduction of Pt(2+) species. The mechanism of Pt(2+) reduction involves reverse oxygen spillover and formation of oxygen vacancies on Pt-CeO2 films. Our calculations suggest the existence of a threshold concentration of oxygen vacancies associated with the onset of Pt(2+) reduction. PMID:26908194

  3. Electrochemical performance of a solid oxide fuel cell with an anode based on Cu-Ni/CeO2 for methane direct oxidation

    NASA Astrophysics Data System (ADS)

    Hornés, Aitor; Escudero, María J.; Daza, Loreto; Martínez-Arias, Arturo

    2014-03-01

    A CuNi-CeO2/YSZ/LSF solid oxide fuel cell has been fabricated and tested with respect to its electrochemical activity for direct oxidation of dry methane. The electrodes have been prepared by impregnation of corresponding porous YSZ layers, using reverse microemulsions as impregnating medium for the anode (constituted by Cu-Ni at 1:1 atomic ratio in combination with CeO2). On the basis of I-V electrochemical testing complemented by impedance spectroscopy (IS) measurements it is shown the ability of the SOFC for direct oxidation of methane in a rather stable way. Differences in the behavior as a function of operating temperature (1023-1073 K) are also revealed and examined on the basis of analysis of IS spectra.

  4. Solid oxide fuel cell process and apparatus

    DOEpatents

    Cooper, Matthew Ellis; Bayless, David J.; Trembly, Jason P.

    2011-11-15

    Conveying gas containing sulfur through a sulfur tolerant planar solid oxide fuel cell (PSOFC) stack for sulfur scrubbing, followed by conveying the gas through a non-sulfur tolerant PSOFC stack. The sulfur tolerant PSOFC stack utilizes anode materials, such as LSV, that selectively convert H.sub.2S present in the fuel stream to other non-poisoning sulfur compounds. The remaining balance of gases remaining in the completely or near H.sub.2S-free exhaust fuel stream is then used as the fuel for the conventional PSOFC stack that is downstream of the sulfur-tolerant PSOFC. A broad range of fuels such as gasified coal, natural gas and reformed hydrocarbons are used to produce electricity.

  5. Energy efficiency enhancement of ethanol electrooxidation on Pd-CeO(2)/C in passive and active polymer electrolyte-membrane fuel cells.

    PubMed

    Bambagioni, Valentina; Bianchini, Claudio; Chen, Yanxin; Filippi, Jonathan; Fornasiero, Paolo; Innocenti, Massimo; Lavacchi, Alessandro; Marchionni, Andrea; Oberhauser, Werner; Vizza, Francesco

    2012-07-01

    Pd nanoparticles have been generated by performing an electroless procedure on a mixed ceria (CeO(2))/carbon black (Vulcan XC-72) support. The resulting material, Pd-CeO(2)/C, has been characterized by means of transmission electron microscopy (TEM), inductively coupled plasma atomic emission spectroscopy (ICP-AES), and X-ray diffraction (XRD) techniques. Electrodes coated with Pd-CeO(2)/C have been scrutinized for the oxidation of ethanol in alkaline media in half cells as well as in passive and active direct ethanol fuel cells (DEFCs). Membrane electrode assemblies have been fabricated using Pd-CeO(2)/C anodes, proprietary Fe-Co cathodes, and Tokuyama anion-exchange membranes. The monoplanar passive and active DEFCs have been fed with aqueous solutions of 10 wt% ethanol and 2 M KOH, supplying power densities as high as 66 mW cm(-2) at 25 °C and 140 mW cm(-2) at 80 °C. A comparison with a standard anode electrocatalyst containing Pd nanoparticles (Pd/C) has shown that, at even metal loading and experimental conditions, the energy released by the cells with the Pd-CeO(2)/C electrocatalyst is twice as much as that supplied by the cells with the Pd/C electrocatalyst. A cyclic voltammetry study has shown that the co-support ceria contributes to the remarkable decrease of the onset oxidation potential of ethanol. It is proposed that ceria promotes the formation at low potentials of species adsorbed on Pd, Pd(I)-OH(ads), that are responsible for ethanol oxidation. PMID:22517591

  6. Cortical entrainment to music and its modulation by expertise

    PubMed Central

    Doelling, Keith B.; Poeppel, David

    2015-01-01

    Recent studies establish that cortical oscillations track naturalistic speech in a remarkably faithful way. Here, we test whether such neural activity, particularly low-frequency (<8 Hz; delta–theta) oscillations, similarly entrain to music and whether experience modifies such a cortical phenomenon. Music of varying tempi was used to test entrainment at different rates. In three magnetoencephalography experiments, we recorded from nonmusicians, as well as musicians with varying years of experience. Recordings from nonmusicians demonstrate cortical entrainment that tracks musical stimuli over a typical range of tempi, but not at tempi below 1 note per second. Importantly, the observed entrainment correlates with performance on a concurrent pitch-related behavioral task. In contrast, the data from musicians show that entrainment is enhanced by years of musical training, at all presented tempi. This suggests a bidirectional relationship between behavior and cortical entrainment, a phenomenon that has not previously been reported. Additional analyses focus on responses in the beta range (∼15–30 Hz)—often linked to delta activity in the context of temporal predictions. Our findings provide evidence that the role of beta in temporal predictions scales to the complex hierarchical rhythms in natural music and enhances processing of musical content. This study builds on important findings on brainstem plasticity and represents a compelling demonstration that cortical neural entrainment is tightly coupled to both musical training and task performance, further supporting a role for cortical oscillatory activity in music perception and cognition. PMID:26504238

  7. Cortical entrainment to music and its modulation by expertise.

    PubMed

    Doelling, Keith B; Poeppel, David

    2015-11-10

    Recent studies establish that cortical oscillations track naturalistic speech in a remarkably faithful way. Here, we test whether such neural activity, particularly low-frequency (<8 Hz; delta-theta) oscillations, similarly entrain to music and whether experience modifies such a cortical phenomenon. Music of varying tempi was used to test entrainment at different rates. In three magnetoencephalography experiments, we recorded from nonmusicians, as well as musicians with varying years of experience. Recordings from nonmusicians demonstrate cortical entrainment that tracks musical stimuli over a typical range of tempi, but not at tempi below 1 note per second. Importantly, the observed entrainment correlates with performance on a concurrent pitch-related behavioral task. In contrast, the data from musicians show that entrainment is enhanced by years of musical training, at all presented tempi. This suggests a bidirectional relationship between behavior and cortical entrainment, a phenomenon that has not previously been reported. Additional analyses focus on responses in the beta range (∼15-30 Hz)-often linked to delta activity in the context of temporal predictions. Our findings provide evidence that the role of beta in temporal predictions scales to the complex hierarchical rhythms in natural music and enhances processing of musical content. This study builds on important findings on brainstem plasticity and represents a compelling demonstration that cortical neural entrainment is tightly coupled to both musical training and task performance, further supporting a role for cortical oscillatory activity in music perception and cognition. PMID:26504238

  8. Laboratory Experiments on Convective Entrainment Using a Saline Water Tank

    NASA Astrophysics Data System (ADS)

    Jonker, Harmen J. J.; Jiménez, Maria A.

    2014-06-01

    Entrainment fluxes in a shear-free convective boundary layer have been measured with a saline water tank set-up. The experiments were targeted towards measuring the entrainment behaviour for medium to high Richardson numbers and use a two-layer design, i.e. two stacked non-stratified (neutral) layers with different densities. With laser induced fluorescence (LIF), the entrainment flux of a fluorescent dye is measured for bulk Richardson numbers in the range 30-260. It is proposed that a carefully chosen combination of top-down and bottom-up processes improves the accuracy of LIF-based entrainment observations. The observed entrainment fluxes are about an order of magnitude lower than reported for thermal water tanks: the derived buoyancy entrainment ratio, , is found to be , which is to be compared with for a thermal convection tank (Deardorff et al., J Fluid Mech 100:41-64, 1980). An extensive discussion is devoted to the influence of the Reynolds and Prandtl numbers in laboratory experiments on entrainment.

  9. Long-term evaluation of solid oxide fuel cell candidate materials in a 3-cell generic stack test fixture, part III: Stability and microstructure of Ce-(Mn,Co)-spinel coating, AISI441 interconnect, alumina coating, cathode and anode

    NASA Astrophysics Data System (ADS)

    Chou, Yeong-Shyung; Stevenson, Jeffry W.; Choi, Jung-Pyung

    2014-07-01

    A generic solid oxide fuel cell stack test fixture was developed to evaluate candidate materials and processing under realistic conditions. Part III of the work investigated the stability of Ce-(Mn,Co) spinel coating, AISI441 metallic interconnect, alumina coating, and cell's degradation. After 6000 h test, the spinel coating showed densification with some diffusion of Cr. At the metal interface, segregation of Si and Ti was observed, however, no continuous layer formed. The alumina coating for perimeter sealing areas appeared more dense and thick at the air side than the fuel side. Both the spinel and alumina coatings remained bonded. EDS analysis of Cr within the metal showed small decrease in concentration near the coating interface and would expect to cause no issue of Cr depletion. Inter-diffusion of Ni, Fe, and Cr between spot-welded Ni wire and AISI441 interconnect was observed and Cr-oxide scale formed along the circumference of the weld. The microstructure of the anode and cathode was discussed relating to degradation of the top and middle cells. Overall, the Ce-(Mn,Co) spinel coating, alumina coating, and AISI441 steel showed the desired long-term stability and the developed generic stack fixture proved to be a useful tool to validate candidate materials for SOFC.

  10. Automated small scale oil seed processing plant for production of fuel for diesel engines

    SciTech Connect

    Thompson, J.C.; Peterson, C.L.

    1982-01-01

    University of Idaho seed processing research is centered about a CeCoCo oil expeller. A seed preheater-auger, seed bin, meal auger, and oil pump have been constructed to complete the system, which is automated and instrumented. The press, preheater, cake removal auger, and oil transfer pump are tied into a central panel where energy use is measured and the process controlled. Extracted oil weight, meal weight, process temperature, and input energy are all recorded during operation. The oil is transferred to tanks where it settles for 48 hours or more. It is then pumped through a filtering system and stored ready to be used as an engine fuel. The plant has processed over 11,000 kg of seed with an average extraction efficiency of 78 percent. 5 tables.

  11. 77 FR 823 - Guidance for Fuel Cycle Facility Change Processes

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-06

    ... Information DG-3037 was published in the Federal Register on July 14, 2011 (76 FR 41527). The public comment... COMMISSION Guidance for Fuel Cycle Facility Change Processes AGENCY: Nuclear Regulatory Commission. ACTION... issuing a new regulatory guide (RG) 3.74, ``Guidance for Fuel Cycle Facility Change Processes.''...

  12. Electrocatalytic and fuel processing studies for portable fuel cells

    NASA Astrophysics Data System (ADS)

    Matter, Paul H.

    In the field of catalysis, the development of alternative catalysts for the oxygen reduction reaction (ORR) in Polymer Electrolyte Membrane Fuel Cell (PEMFC) cathodes has been an ongoing task for researchers over the past two decades. PEM fuel cells are considered to be potential replacements for internal combustion engines in automobiles, and their reduced emissions and better efficiency would have huge payoffs for our environment, and in reducing our nation's dependence on foreign oil. To date, PEMFC cathode over-potentials are still significant, and the only materials discovered to be highly active and stable catalysts in an acidic environment are platinum-based. Despite several major advances in recent years in reducing platinum loading in fuel cell electrodes, the high expense and low availability of platinum will hinder the large-scale commercialization of PEM fuel cells. The most hopeful advances being made in replacing platinum are related to pyrolyzed organic macrocycles with transition metal centers (such as Fe or Co porphyrins and phthalocyanines). Encouragingly, it has recently been discovered that active electrodes could be prepared by heat-treating metal and nitrogen precursors (not necessarily organic macrocycles) together in the presence of a carbon support. In the first study of this dissertation, catalysts for the Oxygen Reduction Reaction (ORR) were prepared by the pyrolysis of acetonitrile over various supports. The supports used included Vulcan Carbon, high purity alumina, silica, magnesia, and these same supports impregnated with Fe, Co, or Ni in the form of acetate salt. The catalysts were characterized by BET surface area analysis, BJH Pore Size Distribution (PSD), conductivity testing, Transmission Electron Microscopy (TEM), Temperature Programmed Oxidation (TPO), Thermo-Gravimetric Analysis (TGA), X-Ray Diffraction (XRD), X-ray Photo-electron Spectroscopy (XPS), Mossbauer Spectroscopy, Rotating Disk Electrode (RDE) half cell testing, and

  13. ARTICLE Ionic Conduction and Fuel Cell Performance of Ba0.98Ce0.8Tm0.2O3-α Ceramic

    NASA Astrophysics Data System (ADS)

    Qiu, Li-gan; Wang, Mao-yuan

    2010-12-01

    The perovskite-type oxide solid solution Ba0.98Ce0.8Tm0.2O3-α was prepared by high temperature solid-state reaction and its single phase character was confirmed by X-ray diffraction. The conduction property of the sample was investigated by alternating current impedance spectroscopy and gas concentration cell methods under different gases atmospheres in the temperature range of 500-900°C. The performance of the hydrogen-air fuel cell using the sample as solid electrolyte was measured. In wet hydrogen, the sample is a pure protonic conductor with the protonic transport number of 1 in the range of 500-600 °C, a mixed conductor of proton and electron with the protonic transport number of 0.945-0.933 above 600 °C. In wet air, the sample is a mixed conductor of proton, oxide ion, and electronic hole. The protonic transport numbers are 0.010-0.021, and the oxide ionic transport numbers are 0.471-0.382. In hydrogen-air fuel cell, the sample is a mixed conductor of proton, oxide ion and electron, the ionic transport numbers are 0.942-0.885. The fuel cell using Ba0.98Ce0.8Tm0.2O3-α as solid electrolyte can work stably. At 900 °C, the maximum power output density is 110.2 mW/cm2, which is higher than that of our previous cell using BaxCe0.8RE0.2O3-α (x<=1, RE=Y, Eu, Ho) as solid electrolyte.

  14. Reduction of Pt2+ species in model Pt-CeO2 fuel cell catalysts upon reaction with methanol

    NASA Astrophysics Data System (ADS)

    Neitzel, Armin; Johánek, Viktor; Lykhach, Yaroslava; Skála, Tomáš; Tsud, Nataliya; Vorokhta, Mykhailo; Matolín, Vladimír; Libuda, Jörg

    2016-11-01

    The stability of atomically dispersed Pt2+ species on the surface of nanostructured CeO2 films during the reaction with methanol has been investigated by means of synchrotron radiation photoelectron spectroscopy and resonant photoemission spectroscopy. The isolated Pt2+ species were prepared at low Pt concentration in Pt-CeO2 film. Additionally, Pt2+ species coexisting with metallic Pt particles were prepared at high Pt concentration. We found that adsorption of methanol yields similar decomposition products regardless of Pt concentration in Pt-CeO2 films. A small number of oxygen vacancies formed during the methanol decomposition can be replenished in the Pt-CeO2 film with low Pt concentration by diffusion of oxygen from the bulk. In the presence of supported Pt particles, a higher number of oxygen vacancies leads to a partial reduction of the Pt2+ species. The isolated Pt2+ species are reduced under rather strongly reducing conditions only, i.e. during annealing under continuous exposure to methanol. Reduction of isolated Pt2+ species results in the formation of ultra-small Pt particles containing around 25 atoms per particle or less. Such ultra-small Pt particles demonstrate excellent stability against sintering during annealing of Pt-CeO2 film with low Pt concentration under reducing conditions.

  15. Measurement of air entrainment in plasma jets

    SciTech Connect

    Fincke, J.R.; Rodriquez, R.; Pentecost, C.G.

    1990-01-01

    The concentration and temperature of air entrained into argon and helium plasma jets has been measured using coherent anti-Stokes Raman spectroscopy (CARS). The argon plasma flow field is characterized by a short region of well behaved laminar flow near the nozzle exit followed by an abrupt transition to turbulence. Once the transition of turbulence occurs, air is rapidly mixed into the jet core. The location of the transition region is determined by the rapid cooling of the jet and the resulting increase in Reynolds number. In contrast, the helium plasma flow field never exceeds a Reynolds number of 200 and remains laminar. The entrainment process in this case is controlled by molecular diffusion rather than turbulent mixing. 9 refs., 5 figs., 1 tab.

  16. Measurement of air entrainment in plasma jets

    NASA Astrophysics Data System (ADS)

    Fincke, J. R.; Rodriquez, R.; Pentecost, C. G.

    The concentration and temperature of air entrained into argon and helium plasma jets has been measured using coherent anti-Stokes Raman spectroscopy (CARS). The argon plasma flow field is characterized by a short region of well behaved laminar flow near the nozzle exit followed by an abrupt transition to turbulence. Once the transition of turbulence occurs, air is rapidly mixed into the jet core. The location of the transition region is determined by the rapid cooling of the jet and the resulting increase in Reynolds number. In contrast, the helium plasma flow field never exceeds a Reynolds number of 200 and remains laminar. The entrainment process in this case is controlled by molecular diffusion rather than turbulent mixing.

  17. Analysis of the electrochemical performance of MoNi-CeO2 cermet as anode material for solid oxide fuel cell. Part I. H2, CH4 and H2/CH4 mixtures as fuels

    NASA Astrophysics Data System (ADS)

    Escudero, M. J.; Gómez de Parada, I.; Fuerte, A.; Serrano, J. L.

    2014-05-01

    This paper investigates the catalytic activity and the electrochemical performance of bimetallic formulation combining Mo and Ni with CeO2 (MoNi-Ce) in relation its potential use as anode material for SOFC. The catalytic properties were evaluated for methane partial oxidation as function of temperature and the carbon deposition on the anode surface was analysed by TG-MS. A conversion of 12.8% was reached for partial methane oxidation at 850 °C as well as a high coke resistance. The electrochemical performance was studied in a single cell with La0.58Sr0.4Fe0.8Co0.2O3-δ (LSCF) as cathode, La0.9Sr0.1Ga0.8Mg0.2O2.85 (LSGM) as electrolyte and MoNi-Ce as anode. A thin buffer layer of La0.4Ce0.6O4-δ (LCD) between anode and electrolyte was used to avoid possible interfacial reactions. The cell was tested in different humidified fuels (H2, CH4 and H2/CH4 mixtures) and static air at 750, 800 and 850 °C. The electrochemical behaviour was evaluated by current-voltage curves, impedance spectroscopy and load demand. Stability tests were also performed in pure CH4 at each studied temperature in order to assess degradation of the electrochemical cell performance. No significant performance degradation was detected in all studied fuels even pure methane, which suggests that MoNi-Ce is a suitable anode material for direct methane SOFC.

  18. Fuel quality/processing study. Volume 4: On site processing studies

    NASA Technical Reports Server (NTRS)

    Jones, G. E., Jr.; Cutrone, M.; Doering, H.; Hickey, J.

    1981-01-01

    Fuel treated at the turbine and the turbine exhaust gas processed at the turbine site are studied. Fuel treatments protect the turbine from contaminants or impurities either in the upgrading fuel as produced or picked up by the fuel during normal transportation. Exhaust gas treatments provide for the reduction of NOx and SOx to environmentally acceptable levels. The impact of fuel quality upon turbine maintenance and deterioration is considered. On site costs include not only the fuel treatment costs as such, but also incremental costs incurred by the turbine operator if a turbine fuel of low quality is not acceptably upgraded.

  19. A FIRE-ACE/SHEBA Case Study of Mixed-Phase Arctic Boundary Layer Clouds: Entrainment Rate Limitations on Rapid Primary Ice Nucleation Processes

    NASA Technical Reports Server (NTRS)

    Fridlin, Ann; vanDiedenhoven, Bastiaan; Ackerman, Andrew S.; Avramov, Alexander; Mrowiec, Agnieszka; Morrison, Hugh; Zuidema, Paquita; Shupe, Matthew D.

    2012-01-01

    Observations of long-lived mixed-phase Arctic boundary layer clouds on 7 May 1998 during the First International Satellite Cloud Climatology Project (ISCCP) Regional Experiment (FIRE)Arctic Cloud Experiment (ACE)Surface Heat Budget of the Arctic Ocean (SHEBA) campaign provide a unique opportunity to test understanding of cloud ice formation. Under the microphysically simple conditions observed (apparently negligible ice aggregation, sublimation, and multiplication), the only expected source of new ice crystals is activation of heterogeneous ice nuclei (IN) and the only sink is sedimentation. Large-eddy simulations with size-resolved microphysics are initialized with IN number concentration N(sub IN) measured above cloud top, but details of IN activation behavior are unknown. If activated rapidly (in deposition, condensation, or immersion modes), as commonly assumed, IN are depleted from the well-mixed boundary layer within minutes. Quasi-equilibrium ice number concentration N(sub i) is then limited to a small fraction of overlying N(sub IN) that is determined by the cloud-top entrainment rate w(sub e) divided by the number-weighted ice fall speed at the surface v(sub f). Because w(sub c)< 1 cm/s and v(sub f)> 10 cm/s, N(sub i)/N(sub IN)<< 1. Such conditions may be common for this cloud type, which has implications for modeling IN diagnostically, interpreting measurements, and quantifying sensitivity to increasing N(sub IN) (when w(sub e)/v(sub f)< 1, entrainment rate limitations serve to buffer cloud system response). To reproduce observed ice crystal size distributions and cloud radar reflectivities with rapidly consumed IN in this case, the measured above-cloud N(sub IN) must be multiplied by approximately 30. However, results are sensitive to assumed ice crystal properties not constrained by measurements. In addition, simulations do not reproduce the pronounced mesoscale heterogeneity in radar reflectivity that is observed.

  20. Production of synthetic fuels using syngas from a steam hydrogasification and reforming process

    NASA Astrophysics Data System (ADS)

    Raju, Arun Satheesh Kumar

    from carbonaceous feedstocks. Experimental work on the Fischer-Tropsch synthesis has also been performed. A life cycle analysis has been performed with the objective of comparing the life cycle energy consumption and emissions of synthetic diesel fuel produced through the CE-CERT process with other fuel/vehicle combinations. The experimental and simulation results presented here demonstrate that the CE-CERT process is versatile and can potentially handle a number of different feedstocks. CE-CERT process appears to be suitable for commercialization in very large scales with a coal feedstock and also in a distributed network of smaller scale reactors utilizing localized renewable feedstocks.

  1. Entrainment and detrainment in a simple cumulus cloud model

    NASA Technical Reports Server (NTRS)

    Randall, D. A.; Huffman, G. J.

    1982-01-01

    A cumulus cloud model, analogous to the mixed-layer models of the planetary boundary layer and the upper ocean, is developed using a single, unitary entrainment process in which the motion of the cloud boundary relative to the mean flow is permitted, produced, and controlled by turbulent processes. An alternate theory to the mixing-length theory of Asai and Kasahara (1967) is proposed which completely removes the strong scale-dependence of the Asai-Kasahara model. The model reintroduces scale-dependence by introducing including the pe5turbation pressure term of the equation of vertical motion. It is shown that the model predicts deeper clouds than the Asai-Kasahara model for a given sounding, due to the entrainment assumption and the effects of the perturbation pressure. Lateral entrainment dominates cloud-top entrainment, although finite-difference errors increase the cloud-top entrainment rate from zero to a positive value in actual situations. The fractional entrainment rate for updrafts is determined to vary only slightly with height and to decrease only slowly as the cloud radius increases, while the fractional detrainment rate for updrafts increases with height.

  2. Differential Entrainment of Neuroelectric Delta Oscillations in Developmental Dyslexia

    PubMed Central

    Soltész, Fruzsina; Szűcs, Denes; Leong, Victoria; White, Sonia; Goswami, Usha

    2013-01-01

    Oscillatory entrainment to the speech signal is important for language processing, but has not yet been studied in developmental disorders of language. Developmental dyslexia, a difficulty in acquiring efficient reading skills linked to difficulties with phonology (the sound structure of language), has been associated with behavioural entrainment deficits. It has been proposed that the phonological ‘deficit’ that characterises dyslexia across languages is related to impaired auditory entrainment to speech at lower frequencies via neuroelectric oscillations (<10 Hz, ‘temporal sampling theory’). Impaired entrainment to temporal modulations at lower frequencies would affect the recovery of the prosodic and syllabic structure of speech. Here we investigated event-related oscillatory EEG activity and contingent negative variation (CNV) to auditory rhythmic tone streams delivered at frequencies within the delta band (2 Hz, 1.5 Hz), relevant to sampling stressed syllables in speech. Given prior behavioural entrainment findings at these rates, we predicted functionally atypical entrainment of delta oscillations in dyslexia. Participants performed a rhythmic expectancy task, detecting occasional white noise targets interspersed with tones occurring regularly at rates of 2 Hz or 1.5 Hz. Both groups showed significant entrainment of delta oscillations to the rhythmic stimulus stream, however the strength of inter-trial delta phase coherence (ITC, ‘phase locking’) and the CNV were both significantly weaker in dyslexics, suggestive of weaker entrainment and less preparatory brain activity. Both ITC strength and CNV amplitude were significantly related to individual differences in language processing and reading. Additionally, the instantaneous phase of prestimulus delta oscillation predicted behavioural responding (response time) for control participants only. PMID:24204644

  3. New insight into the promoting role of process on the CeO₂-WO₃/TiO₂ catalyst for NO reduction with NH₃ at low-temperature.

    PubMed

    Zhang, Shule; Zhong, Qin; Shen, Yuge; Zhu, Li; Ding, Jie

    2015-06-15

    This study aimed at investigating the reason of high catalytic activity for CeO2-WO3/TiO2 catalyst from the aspects of WO3 interaction with other species and the NO oxidation process. Analysis by X-ray diffractometry, photoluminescence spectra, diffuse reflectance UV-visible, X-ray photoelectron spectroscopy, density functional theory calculations, electron paramagnetic resonance spectroscopy, temperature-programmed-desorption of NO and in situ diffuse reflectance infrared transform spectroscopy showed that WO3 could interact with CeO2 to improve the electron gaining capability of CeO2 species. In addition, WO3 species acted as electron donating groups to transfer the electrons to CeO2 species. The two aspects enhanced the formation of reduced CeO2 species to improve the formation of superoxide ions. Furthermore, the Ce species were the active sites for the NO adsorption and the superoxide ions over the catalyst needed oxidizing the adsorbed NO to improve the NO oxidation. This process was responsible for the high catalytic activity of CeO2-WO3/TiO2 catalyst. PMID:25746195

  4. Fluid Dynamics of Pressurized, Entrained Coal Gasifiers

    SciTech Connect

    1997-12-31

    Pressurized, entrained gasification is a promising new technology for the clean and efficient combustion of coal. Its principle is to operate a coal gasifier at a high inlet gas velocity to increase the inflow of reactants, and at an elevated pressure to raise the overall efficiency of the process. Unfortunately, because of the extraordinary difficulties involved in performing measurements in hot, pressurized, high-velocity pilot plants, its fluid dynamics are largely unknown. Thus the designer cannot predict with certainty crucial phenomena like erosion, heat transfer and solid capture. In this context, we are conducting a study of the fluid dynamics of Pressurized Entrained Coal Gasifiers (PECGs). The idea is to simulate the flows in generic industrial PECGs using dimensional similitude. To this end, we employ a unique entrained gas-solid flow facility with the flexibility to recycle -rather than discard- gases other than air. By matching five dimensionless parameters, suspensions in mixtures of helium, carbon dioxide and sulfur hexafluoride simulate the effects of pressure and scale-up on the fluid dynamics of PECGS. Because it operates under cold, atmospheric conditions, the laboratory facility is ideal for detailed measurements. These activities are conducted with Air Products & Chemicals, Inc., which is a member of a consortium that includes Foster Wheeler and Deutsche Babcock Energie- und Umwelttechnik AG.

  5. Fuel quality-processing study. Volume 2: Literature survey

    NASA Technical Reports Server (NTRS)

    Jones, G. E., Jr.; Amero, R.; Murthy, B.; Cutrone, M.

    1981-01-01

    The validity of initial assumptions about raw materials choices and relevant upgrading processing options was confirmed. The literature survey also served to define the on-site (at the turbine location) options for fuel treatment and exhaust gas treatment. The literature survey also contains a substantial compilation of specification and physical property information about liquid fuel products relevant to industrial gas turbines.

  6. Treatment of oxide spent fuel using the lithium reduction process

    SciTech Connect

    Karell, E.J.; Pierce, R.D.; Mulcahey, T.P.

    1996-05-01

    The wide variety in the composition of DOE spent nuclear fuel complicates its long-term disposition because of the potential requirement to individually qualify each type of fuel for repository disposal. Argonne National Laboratory (ANL) has developed the electrometallurgical treatment technique to convert all of these spent fuel types into a single set of disposal forms, simplifying the qualification process. While metallic fuels can be directly processed using the electrometallurgical treatment technique, oxide fuels must first be reduced to the metallic form. The lithium reduction process accomplishes this pretreatment. In the lithium process the oxide components of the fuel are reduced using lithium at 650 C in the presence of molten LiCl, yielding the corresponding metals and Li{sub 2}O. The reduced metal components are then separated from the LiCl salt phase and become the feed material for electrometallurgical treatment. A demonstration test of the lithium reduction process was successfully conducted using a 10-kg batch of simulated oxide spent fuel and engineering-scale equipment specifically constructed for that purpose. This paper describes the lithium process, the equipment used in the demonstration test, and the results of the demonstration test.

  7. Air entrainment in hairy surfaces

    NASA Astrophysics Data System (ADS)

    Nasto, Alice; Regli, Marianne; Brun, P.-T.; Alvarado, José; Clanet, Christophe; Hosoi, A. E.

    2016-07-01

    Motivated by diving semiaquatic mammals, we investigate the mechanism of dynamic air entrainment in hairy surfaces submerged in liquid. Hairy surfaces are cast out of polydimethylsiloxane elastomer and plunged into a fluid bath at different velocities. Experimentally, we find that the amount of air entrained is greater than what is expected for smooth surfaces. Theoretically, we show that the hairy surface can be considered as a porous medium and we describe the air entrainment via a competition between the hydrostatic forcing and the viscous resistance in the pores. A phase diagram that includes data from our experiments and biological data from diving semiaquatic mammals is included to place the model system in a biological context and predict the regime for which the animal is protected by a plastron of air.

  8. Material Properties Governing Co-Current Flame Spread: The Effect of Air Entrainment

    NASA Technical Reports Server (NTRS)

    Coutin, Mickael; Rangwala, Ali S.; Torero, Jose L.; Buckley, Steven G.

    2003-01-01

    A study on the effects of lateral air entrainment on an upward spreading flame has been conducted. The fuel is a flat PMMA plate of constant length and thickness but variable width. Video images and surface temperatures have allowed establishing the progression of the pyrolyis front and on the flame stand-off distance. These measurements have been incorporated into a theoretical formulation to establish characteristic mass transfer numbers ("B" numbers). The mass transfer number is deemed as a material related parameter that could be used to assess the potential of a material to sustain co-current flame spread. The experimental results show that the theoretical formulation fails to describe heat exchange between the flame and the surface. The discrepancies seem to be associated to lateral air entrainment that lifts the flame off the surface and leads to an over estimation of the local mass transfer number. Particle Image Velocimetry (PIV) measurements are in the process of being acquired. These measurements are intended to provide insight on the effect of air entrainment on the flame stand-off distance. A brief description of the methodology to be followed is presented here.

  9. Large Eddy Simulation of the fuel transport and mixing process in a scramjet combustor with rearwall-expansion cavity

    NASA Astrophysics Data System (ADS)

    Cai, Zun; Liu, Xiao; Gong, Cheng; Sun, Mingbo; Wang, Zhenguo; Bai, Xue-Song

    2016-09-01

    Large Eddy Simulation (LES) was employed to investigate the fuel/oxidizer mixing process in an ethylene fueled scramjet combustor with a rearwall-expansion cavity. The numerical solver was first validated for an experimental flow, the DLR strut-based scramjet combustor case. Shock wave structures and wall-pressure distribution from the numerical simulations were compared with experimental data and the numerical results were shown in good agreement with the available experimental data. Effects of the injection location on the flow and mixing process were then studied. It was found that with a long injection distance upstream the cavity, the fuel is transported much further into the main flow and a smaller subsonic zone is formed inside the cavity. Conversely, with a short injection distance, the fuel is entrained more into the cavity and a larger subsonic zone is formed inside the cavity, which is favorable for ignition in the cavity. For the rearwall-expansion cavity, it is suggested that the optimized ignition location with a long upstream injection distance should be in the bottom wall in the middle part of the cavity, while the optimized ignition location with a short upstream injection distance should be in the bottom wall in the front side of the cavity. By employing a cavity direct injection on the rear wall, the fuel mass fraction inside the cavity and the local turbulent intensity will both be increased due to this fueling, and it will also enhance the mixing process which will also lead to increased mixing efficiency. For the rearwall-expansion cavity, the combined injection scheme is expected to be an optimized injection scheme.

  10. Entrainment of Air into Vertical Jets in a Crosswind

    NASA Astrophysics Data System (ADS)

    Roberts, K. K.; Solovitz, S.; Freedland, G.; Camp, E.; Cal, R. B.; Mastin, L. G.

    2015-12-01

    During volcanic eruptions, ash concentration must be determined for aviation safety, but the limiting threshold is difficult to distinguish visually. Computational models are typically used to predict ash concentrations, using inputs such as plume height, eruptive duration, and wind speeds. The models also depend on empirical parameters, such as the entrainment of atmospheric air as a ratio of the air inflow speed and the jet speed. Entrainment of atmospheric air plays a critical role in the behavior of volcanic plumes in the atmosphere, impacting the mass flow rate, buoyancy, and particle concentration of the plume. This process is more complex in a crosswind, leading to greater uncertainty in the model results. To address these issues, a laboratory-scale study has been conducted to improve the entrainment models. Observations of a vertical, unconfined jet are performed using Particle Image Velocimetry, while varying jet density using different compressed gases and Reynolds number. To test the effects of a crosswind on plume entrainment rates, these are then compared with similar jet experiments in a wind tunnel. A series of jet geometries, jet speeds and tunnel speeds are considered. The measured velocities are used to determine the entrainment response, which can be used to determine ash concentration over time as atmospheric air is entrained into the plume. We also quantify the mean and the fluctuations in flow velocity.

  11. Experimental insights on the electron transfer and energy transfer processes between Ce{sup 3+}-Yb{sup 3+} and Ce{sup 3+}-Tb{sup 3+} in borate glass

    SciTech Connect

    Sontakke, Atul D. Katayama, Yumiko; Tanabe, Setsuhisa; Ueda, Jumpei; Dorenbos, Pieter

    2015-03-30

    A facile method to describe the electron transfer and energy transfer processes among lanthanide ions is presented based on the temperature dependent donor luminescence decay kinetics. The electron transfer process in Ce{sup 3+}-Yb{sup 3+} exhibits a steady rise with temperature, whereas the Ce{sup 3+}-Tb{sup 3+} energy transfer remains nearly unaffected. This feature has been investigated using the rate equation modeling and a methodology for the quantitative estimation of interaction parameters is presented. Moreover, the overall consequences of electron transfer and energy transfer process on donor-acceptor luminescence behavior, quantum efficiency, and donor luminescence decay kinetics are discussed in borate glass host. The results in this study propose a straight forward approach to distinguish the electron transfer and energy transfer processes between lanthanide ions in dielectric hosts, which is highly advantageous in view of the recent developments on lanthanide doped materials for spectral conversion, persistent luminescence, and related applications.

  12. Examination of turbulent entrainment-mixing mechanisms using a combined approach

    SciTech Connect

    Lu, C.; Liu, Y.; Niu, S.

    2011-10-01

    Turbulent entrainment-mixing mechanisms are investigated by applying a combined approach to the aircraft measurements of three drizzling and two nondrizzling stratocumulus clouds collected over the U.S. Department of Energy's Atmospheric Radiation Measurement Southern Great Plains site during the March 2000 cloud Intensive Observation Period. Microphysical analysis shows that the inhomogeneous entrainment-mixing process occurs much more frequently than the homogeneous counterpart, and most cases of the inhomogeneous entrainment-mixing process are close to the extreme scenario, having drastically varying cloud droplet concentration but roughly constant volume-mean radius. It is also found that the inhomogeneous entrainment-mixing process can occur both near the cloud top and in the middle level of a cloud, and in both the nondrizzling clouds and nondrizzling legs in the drizzling clouds. A new dimensionless number, the scale number, is introduced as a dynamical measure for different entrainment-mixing processes, with a larger scale number corresponding to a higher degree of homogeneous entrainment mixing. Further empirical analysis shows that the scale number that separates the homogeneous from the inhomogeneous entrainment-mixing process is around 50, and most legs have smaller scale numbers. Thermodynamic analysis shows that sampling average of filament structures finer than the instrumental spatial resolution also contributes to the dominance of inhomogeneous entrainment-mixing mechanism. The combined microphysical-dynamical-thermodynamic analysis sheds new light on developing parameterization of entrainment-mixing processes and their microphysical and radiative effects in large-scale models.

  13. Performance of Ni-Fe/gadolinium-doped CeO{sub2} anode supported tubular solid oxide fuel cells using steam reforming of methane

    SciTech Connect

    Liang, B.; Suzuki, T.; Hamamoto, K.; Yamaguchi, T.; Sumi, H.; Fujishiro, Y.; Ingram, B. J.; Carter, J. D.

    2012-03-15

    Iron nanoparticles (Fe{sub 2}O{sub 3}) were added to NiO/gadolinium-doped CeO{sub 2} (GDC) anode supported solid oxide fuel cell (SOFC) for the direct methane-water fuel operation. The cell was co-sintered at 1400 C, and the anode porosity is 31.8%. The main size corresponding to peak volume is around 1.5 {mu}m. When steam and methane directly fed to the cell, the power density is about 0.57 W cm{sup -2} at 650 C. It is the familiar performance for H{sub 2} operation (4 times of flow rate) with same fuel utilization. Compare with the testing temperature of 600 and 650 C, there is almost no carbon fiber deposition at 700 C with steam/methane (S/C) of 5. At the same time, fuel operation of high value of S/C (=3.3) resulted in fiber-like deposition and degradation of power performance based on loading test results.

  14. Electrochemical fluorination for processing of used nuclear fuel

    DOEpatents

    Garcia-Diaz, Brenda L.; Martinez-Rodriguez, Michael J.; Gray, Joshua R.; Olson, Luke C.

    2016-07-05

    A galvanic cell and methods of using the galvanic cell is described for the recovery of uranium from used nuclear fuel according to an electrofluorination process. The galvanic cell requires no input energy and can utilize relatively benign gaseous fluorinating agents. Uranium can be recovered from used nuclear fuel in the form of gaseous uranium compound such as uranium hexafluoride, which can then be converted to metallic uranium or UO.sub.2 and processed according to known methodology to form a useful product, e.g., fuel pellets for use in a commercial energy production system.

  15. Synergize fuel and petrochemical processing plans with catalytic reforming

    SciTech Connect

    1997-03-01

    Depending on the market, refiner`s plans to produce clean fuels and higher value petrochemicals will weigh heavily on the catalytic reformer`s flexibility. It seems that as soon as a timely article related to catalytic reforming operations is published, a new {open_quotes}boutique{close_quotes} gasoline fuel specification is slapped on to existing fuel standards, affecting reformer operations and processing objectives. Just as importantly, the petrochemical market (such as aromatics) that refiners are targeting, can be very fickle. That`s why process engineers have endeavored to maintain an awareness of the flexibility that technology suppliers are building into modern catalytic reformers.

  16. Hydrogen purification for fuel cell using CuO/CeO 2-Al 2O 3 catalyst

    NASA Astrophysics Data System (ADS)

    Maciel, Cristhiane Guimarães; Profeti, Luciene Paula Roberto; Assaf, Elisabete Moreira; Assaf, José Mansur

    CuO/CeO 2, CuO/Al 2O 3 and CuO/CeO 2-Al 2O 3 catalysts, with CuO loading varying from 1 to 5 wt.%, were prepared by the citrate method and applied to the preferential oxidation of carbon monoxide in a reaction medium containing large amounts of hydrogen (PROX-CO). The compounds were characterized ex situ by X-ray diffraction, specific surface area measurements, temperature-programmed reduction and temperature-programmed reduction of oxidized surfaces; XANES-PROX in situ experiments were also carried out to study the copper oxidation state under PROX-CO conditions. These analyses showed that in the reaction medium the Cu 0 is present as dispersed particles. On the ceria, these metallic particles are smaller and more finely dispersed, resulting in a stronger metal-support interaction than in CuO/Al 2O 3 or CuO/CeO 2-Al 2O 3 catalysts, providing higher PROX-CO activity and better selectivity in the conversion of CO to CO 2 despite the greater BET area presented by samples supported on alumina. It is also shown that the lower CuO content, the higher metal dispersion and consequently the catalytic activity. The redox properties of the ceria support also contributed to catalytic performance.

  17. Comprehensive modeling and numerical investigation of entrained-flow coal gasifiers

    NASA Astrophysics Data System (ADS)

    Silaen, Armin Karen

    Numerical simulations of coal gasification process inside a generic 2-stage entrained-flow gasifier are carried out using the commercial CFD solver ANSYS/FLUENT. The 3-D Navier-Stokes equations and eight species transport equations are solved with three heterogeneous global reactions, three homogeneous reactions, and one thermal cracking equation of volatiles. Finite rates are used for the heterogeneous solid-gas reactions. Both finite rate and eddy-breakup combustion models are calculated for each homogeneous gas-gas reaction, and the smaller of the two rates is used. Lagrangian-Eulerian method is employed. The Eulerian method calculates the continuous phase while the Lagrangian method tracks each coal particle. Fundamental study is carried out to investigate effects of five turbulence models (standard k-epsilon, k-o, RSM, k-o SST, and k-epsilon RNG) and four devolatilization models (Kobayashi, single rate, constant rate, and CPD) on gasification simulation. A study is also conducted to investigate the effects of different operation parameters on gasification process including coal mixture (dry vs. slurry), oxidant (oxygen-blown vs. air-blown), and different coal distributions between two stages. Finite-rate model and instantaneous gasification model are compared. It is revealed that the instantaneous gasification approach can provide an overall evaluation of relative changes of gasifier performance in terms of temperature, heating value, and gasification efficiency corresponding to parametric variations, but not adequately capture the local gasification process predicted by the finite rate model in most part of the gasifier. Simulations are performed to help with design modifications of a small industrial demonstration entrained-flow gasifier. It is discovered that the benefit of opening the slag tap on the quench-type gasifier wider by allowing slag to move successfully without clogging is compromised by increased heat losses, reduced gasification performance

  18. Timescales of massive human entrainment.

    PubMed

    Fusaroli, Riccardo; Perlman, Marcus; Mislove, Alan; Paxton, Alexandra; Matlock, Teenie; Dale, Rick

    2015-01-01

    The past two decades have seen an upsurge of interest in the collective behaviors of complex systems composed of many agents entrained to each other and to external events. In this paper, we extend the concept of entrainment to the dynamics of human collective attention. We conducted a detailed investigation of the unfolding of human entrainment--as expressed by the content and patterns of hundreds of thousands of messages on Twitter--during the 2012 US presidential debates. By time-locking these data sources, we quantify the impact of the unfolding debate on human attention at three time scales. We show that collective social behavior covaries second-by-second to the interactional dynamics of the debates: A candidate speaking induces rapid increases in mentions of his name on social media and decreases in mentions of the other candidate. Moreover, interruptions by an interlocutor increase the attention received. We also highlight a distinct time scale for the impact of salient content during the debates: Across well-known remarks in each debate, mentions in social media start within 5-10 seconds after it occurs; peak at approximately one minute; and slowly decay in a consistent fashion across well-known events during the debates. Finally, we show that public attention after an initial burst slowly decays through the course of the debates. Thus we demonstrate that large-scale human entrainment may hold across a number of distinct scales, in an exquisitely time-locked fashion. The methods and results pave the way for careful study of the dynamics and mechanisms of large-scale human entrainment. PMID:25880357

  19. Irregular Speech Rate Dissociates Auditory Cortical Entrainment, Evoked Responses, and Frontal Alpha

    PubMed Central

    Kayser, Stephanie J.; Ince, Robin A.A.; Gross, Joachim

    2015-01-01

    The entrainment of slow rhythmic auditory cortical activity to the temporal regularities in speech is considered to be a central mechanism underlying auditory perception. Previous work has shown that entrainment is reduced when the quality of the acoustic input is degraded, but has also linked rhythmic activity at similar time scales to the encoding of temporal expectations. To understand these bottom-up and top-down contributions to rhythmic entrainment, we manipulated the temporal predictive structure of speech by parametrically altering the distribution of pauses between syllables or words, thereby rendering the local speech rate irregular while preserving intelligibility and the envelope fluctuations of the acoustic signal. Recording EEG activity in human participants, we found that this manipulation did not alter neural processes reflecting the encoding of individual sound transients, such as evoked potentials. However, the manipulation significantly reduced the fidelity of auditory delta (but not theta) band entrainment to the speech envelope. It also reduced left frontal alpha power and this alpha reduction was predictive of the reduced delta entrainment across participants. Our results show that rhythmic auditory entrainment in delta and theta bands reflect functionally distinct processes. Furthermore, they reveal that delta entrainment is under top-down control and likely reflects prefrontal processes that are sensitive to acoustical regularities rather than the bottom-up encoding of acoustic features. SIGNIFICANCE STATEMENT The entrainment of rhythmic auditory cortical activity to the speech envelope is considered to be critical for hearing. Previous work has proposed divergent views in which entrainment reflects either early evoked responses related to sound encoding or high-level processes related to expectation or cognitive selection. Using a manipulation of speech rate, we dissociated auditory entrainment at different time scales. Specifically, our

  20. Doing Duo - a case study of entrainment in William Forsythe's choreography "Duo".

    PubMed

    Waterhouse, Elizabeth; Watts, Riley; Bläsing, Bettina E

    2014-01-01

    Entrainment theory focuses on processes in which interacting (i.e., coupled) rhythmic systems stabilize, producing synchronization in the ideal sense, and forms of phase related rhythmic coordination in complex cases. In human action, entrainment involves spatiotemporal and social aspects, characterizing the meaningful activities of music, dance, and communication. How can the phenomenon of human entrainment be meaningfully studied in complex situations such as dance? We present an in-progress case study of entrainment in William Forsythe's choreography Duo, a duet in which coordinated rhythmic activity is achieved without an external musical beat and without touch-based interaction. Using concepts of entrainment from different disciplines as well as insight from Duo performer Riley Watts, we question definitions of entrainment in the context of dance. The functions of chorusing, turn-taking, complementary action, cues, and alignments are discussed and linked to supporting annotated video material. While Duo challenges the definition of entrainment in dance as coordinated response to an external musical or rhythmic signal, it supports the definition of entrainment as coordinated interplay of motion and sound production by active agents (i.e., dancers) in the field. Agreeing that human entrainment should be studied on multiple levels, we suggest that entrainment between the dancers in Duo is elastic in time and propose how to test this hypothesis empirically. We do not claim that our proposed model of elasticity is applicable to all forms of human entrainment nor to all examples of entrainment in dance. Rather, we suggest studying higher order phase correction (the stabilizing tendency of entrainment) as a potential aspect to be incorporated into other models. PMID:25374522

  1. A Brief Review of Past INL Work Assessing Radionuclide Content in TMI-2 Melted Fuel Debris: The Use of 144Ce as a Surrogate for Pu Accountancy

    SciTech Connect

    D. L. Chichester; S. J. Thompson

    2013-09-01

    This report serves as a literature review of prior work performed at Idaho National Laboratory, and its predecessor organizations Idaho National Engineering Laboratory (INEL) and Idaho National Engineering and Environmental Laboratory (INEEL), studying radionuclide partitioning within the melted fuel debris of the reactor of the Three Mile Island 2 (TMI-2) nuclear power plant. The purpose of this review is to document prior published work that provides supporting evidence of the utility of using 144Ce as a surrogate for plutonium within melted fuel debris. When the TMI-2 accident occurred no quantitative nondestructive analysis (NDA) techniques existed that could assay plutonium in the unconventional wastes from the reactor. However, unpublished work performed at INL by D. W. Akers in the late 1980s through the 1990s demonstrated that passive gamma-ray spectrometry of 144Ce could potentially be used to develop a semi-quantitative correlation for estimating plutonium content in these materials. The fate and transport of radioisotopes in fuel from different regions of the core, including uranium, fission products, and actinides, appear to be well characterized based on the maximum temperature reached by fuel in different parts of the core and the melting point, boiling point, and volatility of those radioisotopes. Also, the chemical interactions between fuel, fuel cladding, control elements, and core structural components appears to have played a large role in determining when and how fuel relocation occurred in the core; perhaps the most important of these reaction appears to be related to the formation of mixed-material alloys, eutectics, in the fuel cladding. Because of its high melting point, low volatility, and similar chemical behavior to plutonium, the element cerium appears to have behaved similarly to plutonium during the evolution of the TMI-2 accident. Anecdotal evidence extrapolated from open-source literature strengthens this logical feasibility for

  2. Evaluation of gasification and gas cleanup processes for use in molten-carbonate fuel-cell power plants. Task B interim report

    SciTech Connect

    Not Available

    1981-12-01

    This interim report satisfies the Task B requirement for DOE Contract DE-AC21-81MC16220 to define process configurations for systems suitable for supplying fuel to molten carbonate fuel cells (MCFC) in industrial and utility power plants. The information and data necessary for this study were extracted from sources in the public domain, including reports from DOE, EPRI, and EPA; work sponsored in whole or in part by Federal agencies; and from trade journals, MCFC developers, and manufacturers. The configurations include entrained, fluidized-bed, gravitating-bed, and molten salt gasifiers, both air and oxygen blown. Desulfurization systems utilizing wet scrubbing processes, such as Selexol and Rectisol II, and dry sorbents, such as iron oxide and dolomite, were chosen for evaluation.

  3. Simulating entrainment and particle fluxes in stratified estuaries

    SciTech Connect

    Jensen, A.; Jirka, G.; Lion, L.W.; Brunk, B.

    1999-04-01

    Settling and entrainment are the dominant processes governing noncohesive particle concentration throughout the water column of salt-wedge estuaries. Determination of the relative contribution of these transport processes is complicated by vertical gradients in turbulence and fluid density. A differential-turbulence column (DTC) was designed to simulate a vertical section of a natural water column. With satisfactory characterization of turbulence dissipation and saltwater entrainment, the DTC facilitates controlled studies of suspended particles under estuarine conditions. The vertical decay of turbulence in the DTC was found to obey standard scaling law relations when the characteristic length scale for turbulence in the apparatus was incorporated. The entrainment rate of a density interface also followed established grid-stirred turbulence scaling laws. These relations were used to model the change in concentration of noncohesive particles above a density interface. Model simulations and experimental data from the DTC were consistent over the range of conditions encountered in natural salt-wedge estuaries. Results suggest that when the ratio of entrainment rate to particle settling velocity is small, sedimentation is the dominant transport process, while entrainment becomes significant as the ratio increases.

  4. Analysis of the ATR fuel element swaging process

    SciTech Connect

    Richins, W.D.; Miller, G.K.

    1995-12-01

    This report documents a detailed evaluation of the swaging process used to connect fuel plates to side plates in Advanced Test Reactor (ATR) fuel elements. The swaging is a mechanical process that begins with fitting a fuel plate into grooves in the side plates. Once a fuel plate is positioned, a lip on each of two side plate grooves is pressed into the fuel plate using swaging wheels to form the joints. Each connection must have a specified strength (measured in terms, of a pullout force capacity) to assure that these joints do not fail during reactor operation. The purpose of this study is to analyze the swaging process and associated procedural controls, and to provide recommendations to assure that the manufacturing process produces swaged connections that meet the minimum strength requirement. The current fuel element manufacturer, Babcock and Wilcox (B&W) of Lynchburg, Virginia, follows established procedures that include quality inspections and process controls in swaging these connections. The procedures have been approved by Lockheed Martin Idaho Technologies and are designed to assure repeatability of the process and structural integrity of each joint. Prior to July 1994, ATR fuel elements were placed in the Hydraulic Test Facility (HTF) at the Idaho National Engineering Laboratory (AGNAIL), Test Reactor Area (TRA) for application of Boehmite (an aluminum oxide) film and for checking structural integrity before placement of the elements into the ATR. The results presented in this report demonstrate that the pullout strength of the swaged connections is assured by the current manufacturing process (with several recommended enhancements) without the need for- testing each element in the HTF.

  5. Process for separating water and solids from fuels

    SciTech Connect

    Filho, J.H.; Bachmann, D.L.

    1987-11-17

    A process for separating water and solid particles from a fuel oil feedstock is described comprising: subjecting the feedstock to a first separation in a scroll type centrifugal separator to form a first recovered fuel stream and an oil cake; subjecting at least the first recovered fuel stream to a second separation in a centrifugal disc separator to form a clean fuel stream, an oil-bearing water stream and a sludge stream; treating the oil-bearing water stream in a separator to recover the oil; treating the oil cake removed from the first separation with a solvent in order to form a suspension; mixing the suspension with the sludge stream to form a mixture; feeding the mixture to a filter press to yield a solid reject and a filtrate; separating the filtrate into a decantate and recovered oil; mixing at least a portion of the recovered oil with first recovered fuel stream to form a semi-cleaned fuel stream; and subjecting the semi-cleaned fuel stream to the second separation in a centrifugal disc separator to form the clean fuel stream.

  6. Distillate fuel-oil processing for phosphoric acid fuel-cell power plants

    SciTech Connect

    Ushiba, K. K.

    1980-02-01

    The current efforts to develop distillate oil-steam reforming processes are reviewed, and the applicability of these processes for integration with the fuel cell are discussed. The development efforts can be grouped into the following processing approaches: high-temperature steam reforming (HTSR); autothermal reforming (ATR); autothermal gasification (AG); and ultra desulfurization followed by steam reforming. Sulfur in the feed is a key problem in the process development. A majority of the developers consider sulfur as an unavoidable contaminant of distillate fuel and are aiming to cope with it by making the process sulfur-tolerant. In the HTSR development, the calcium aluminate catalyst developed by Toyo Engineering represents the state of the art. United Technology (UTC), Engelhard, and Jet Propulsion Laboratory (JPL) are also involved in the HTSR research. The ATR of distillate fuel is investigated by UTC and JPL. The autothermal gasification (AG) of distillate fuel is being investigated by Engelhard and Siemens AG. As in the ATR, the fuel is catalytically gasified utilizing the heat generated by in situ partial combustion of feed, however, the goal of the AG is to accomplish the initial breakdown of the feed into light gases and not to achieve complete conversion to CO and H/sub 2/. For the fuel-cell integration, a secondary reforming of the light gases from the AG step is required. Engelhard is currently testing a system in which the effluent from the AG section enters the steam-reforming section, all housed in a single vessel. (WHK)

  7. A Pd/C-CeO2 Anode Catalyst for High-Performance Platinum-Free Anion Exchange Membrane Fuel Cells.

    PubMed

    Miller, Hamish A; Lavacchi, Alessandro; Vizza, Francesco; Marelli, Marcello; Di Benedetto, Francesco; D'Acapito, Francesco; Paska, Yair; Page, Miles; Dekel, Dario R

    2016-05-10

    One of the biggest obstacles to the dissemination of fuel cells is their cost, a large part of which is due to platinum (Pt) electrocatalysts. Complete removal of Pt is a difficult if not impossible task for proton exchange membrane fuel cells (PEM-FCs). The anion exchange membrane fuel cell (AEM-FC) has long been proposed as a solution as non-Pt metals may be employed. Despite this, few examples of Pt-free AEM-FCs have been demonstrated with modest power output. The main obstacle preventing the realization of a high power density Pt-free AEM-FC is sluggish hydrogen oxidation (HOR) kinetics of the anode catalyst. Here we describe a Pt-free AEM-FC that employs a mixed carbon-CeO2 supported palladium (Pd) anode catalyst that exhibits enhanced kinetics for the HOR. AEM-FC tests run on dry H2 and pure air show peak power densities of more than 500 mW cm(-2) . PMID:27062251

  8. Preferential oxidation of methanol and carbon monoxide for gas cleanup during methanol fuel processing

    SciTech Connect

    Birdsell, S.A.; Vanderborgh, N.E.; Inbody, M.A.

    1993-07-01

    Methanol fuel processing generates hydrogen for low-temperature, PEM fuel cell systems now being considered for transportation and other applications. Although liquid methanol fuel is convenient for this application, existing fuel processing techniques generate contaminants that degrade fuel cell performance. Through mathematical models and laboratory experiments chemical processing is described that removes CO and other contaminants from the anode feed stream.

  9. Optimum catalytic process for alcohol fuels from syngas

    SciTech Connect

    Not Available

    1990-04-28

    The objectives of this contract are to discover and evaluate the catalytic properties of novel homogeneous, heterogeneous, or combination catalytic systems for the production of alcohol fuel extenders from syngas, to evaluate analytically and on the bench scale novel reactor concepts for use in converting syngas to liquid fuel products, and to develop on the bench scale the best combination of chemistry, reactor, and total process configuration to achieve the minimum product cost for conversion of syngas to liquid fuel products. Methanol production and heterogeneous catalysis utilizing transition elements supported on metal oxides with spinel structure are discussed. 12 figs., 16 tabs.

  10. Process of producing liquid hydrocarbon fuels from biomass

    DOEpatents

    Kuester, James L.

    1987-07-07

    A continuous thermochemical indirect liquefaction process to convert various biomass materials into diesel-type transportation fuels which fuels are compatible with current engine designs and distribution systems comprising feeding said biomass into a circulating solid fluidized bed gasification system to produce a synthesis gas containing olefins, hydrogen and carbon monoxide and thereafter introducing the synthesis gas into a catalytic liquefaction system to convert the synthesis gas into liquid hydrocarbon fuel consisting essentially of C.sub.7 -C.sub.17 paraffinic hydrocarbons having cetane indices of 50+.

  11. Process of producing liquid hydrocarbon fuels from biomass

    DOEpatents

    Kuester, J.L.

    1987-07-07

    A continuous thermochemical indirect liquefaction process is described to convert various biomass materials into diesel-type transportation fuels which fuels are compatible with current engine designs and distribution systems comprising feeding said biomass into a circulating solid fluidized bed gasification system to produce a synthesis gas containing olefins, hydrogen and carbon monoxide and thereafter introducing the synthesis gas into a catalytic liquefaction system to convert the synthesis gas into liquid hydrocarbon fuel consisting essentially of C[sub 7]-C[sub 17] paraffinic hydrocarbons having cetane indices of 50+. 1 fig.

  12. Microwave Processing of Simulated Advanced Nuclear Fuel Pellets

    SciTech Connect

    D.E. Clark; D.C. Folz

    2010-08-29

    Throughout the three-year project funded by the Department of Energy (DOE) and lead by Virginia Tech (VT), project tasks were modified by consensus to fit the changing needs of the DOE with respect to developing new inert matrix fuel processing techniques. The focus throughout the project was on the use of microwave energy to sinter fully stabilized zirconia pellets using microwave energy and to evaluate the effectiveness of techniques that were developed. Additionally, the research team was to propose fundamental concepts as to processing radioactive fuels based on the effectiveness of the microwave process in sintering the simulated matrix material.

  13. Process review of lignocellulose biochemical conversion to fuel ethanol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This review is meant to give a general technical review of the state-of-the-art in process technology for the biochemical conversion of lignocellulose to fuel ethanol. The proceeding details the chemical structure of biomass and basic process steps needed for extracting carbohydrates as sugars and ...

  14. Entrainment by the jet in HH 47

    NASA Technical Reports Server (NTRS)

    Raymond, John C.; Morse, Jon A.; Hartigan, P.; Curiel, S.; Heathcote, Steve

    1994-01-01

    Fabry-Perot images of the HH 47 optical jet show that the velocity decreases from the center toward the edges which is interpreted as evidence for entrainment. Those images can be used to investigate the rate of entrainment required to account for the observed luminosity. Entrainment along the jet can account for only small fractions of the jet mass and the molecular outflow seen in CO. We compare the density, excitation, and velocity structure of the jet with the predictions of viscous entrainment models and models of entrainment by expulsion of jet material by internal shocks, and find that either type of model can explain the general features.

  15. Entrainment in oscillatory zero-mean flow

    NASA Astrophysics Data System (ADS)

    Medina, P.; Sanchez, M. A.

    2009-04-01

    The dynamical processes associated with the stably stratified atmospheric boundary layer or in the ocean thermocline are less well understood than those of its convective counterparts. This is due to its complexity, and the fact that buoyancy reduces entrainment across density interfaces. We present results on a series of laboratory experiments where a sharp density interface generated by either salt concentration or heat, advances due to grid stirred turbulence. We parametrize the level of buoyancy at the density interface by a local Richardson number defined in terms of the density difference across the interface, which may be due to a temperature or salinity jump. L is the integral lengthscale and u' is the r.m.s. velocity scale. So Ri = C L/u 2. The laboratory experiments were designed to compare the entrainment produced by zero-mean turbulence in heat or salt density interfaces. In the experiment we used a small perspex box of 15 by 10 cm in base, a small mesh grid (M= 0.8 cm ) driven by a motor. So as to generate the density interface by disolving salt in the bottom layer of the water column or by heating the top layer, we added the top light layer, which had a density difference carefully set up by means of a sponge float. The grid was set to oscillate with fixed frequency and stroke at the begining of the experiment and the velocity of advance of the interface Ve was measured by looking at a Shadowgraph or by video recording. The turbulent parameters are derived from previous measurements as a function of the distance between the grid center and the interface z as: l = 0.1 z and the turbulent velocity údecays inversely proportinal to the distance z. There are several mechanisms that produce mixing across the density interface. And there is a dependence of the Prandtl number on the Entrainment law. The entrainment is a power function of the local Richardson number, and the value of the empirical exponent n(Ri,Pr) is compared with previous results. The

  16. Flame Synthesis of Nanosized Cu-Ce-O, Ni-Ce-O, and Fe-Ce-O Catalysts for the Water-Gas Shift (WGS) Reaction

    SciTech Connect

    Pati, R.; Lee, I; Hou, S; Akhuemonkhan, O; Gaskell, K; Wang, Q; Frenkel, A; Chu, D; Salamanca-Riba, L; Ehrman, S

    2009-01-01

    A flame synthesis method has been used to prepare nanosized, high-surface-area Cu-Ce-O, Ni-Ce-O, and Fe-Ce-O catalysts from aqueous solutions of metal acetate precursors. The particles were formed by vaporization of the precursors followed by reaction and then gas to particle conversion. The specific surface areas of the synthesized powders ranged from 127 to 163 m{sup 2}/g. High-resolution transmission electron microscope imaging showed that the particle diameters for the ceria materials are in the range of 3-10 nm, and a thin layer of amorphous material was observed on the surface of the particles. The presence and surface enrichment of the transition-metal oxides (CuO, NiO, and Fe{sub 2}O{sub 3}) on the ceria particles were detected using X-ray photoelectron spectroscopy. Electron energy-loss spectroscopic studies suggest the formation of a core-shell structure in the as-prepared particles. Extended X-ray absorption fine structure studies suggest that the dopants in all M-Ce-O systems are almost isostructural with their oxide counterparts, indicating the doping materials form separate oxide phases (CuO, Fe{sub 2}O{sub 3}, NiO) within the host matrix (CeO{sub 2}). Etching results confirm that most of the transition-metal oxides are present on the surface of CeO{sub 2}, easily dissolved by nitric acid. The performance of the flame-synthesized catalysts was examined toward water-gas shift (WGS) activity for fuel processing applications. The WGS activity of metal ceria catalysts decreases in the order Cu-Ce-O > Ni-Ce-O > Fe-Ce-O > CeO{sub 2} with a feed mixture having a hydrogen to carbon monoxide (H{sub 2}/CO) ratio of 1. There was no methane formation for these catalysts under the tested conditions.

  17. Saturation point representation of cloud-top entrainment instability

    NASA Technical Reports Server (NTRS)

    Boers, Reinout

    1991-01-01

    Cloud-top entrainment instability was investigated using a mixing line analysis. Mixing time scales are closely related to the actual size of the parcel, so that local instabilities are largely dependent on the scales of mixing near the cloud top. Given a fixed transport velocity, variation over a small range of parcel length scales (parcel mixing velocities) turns an energy-producing mixing process into an energy-consuming mixing process. It is suggested that a single criterion for cloud-top entrainment instability will not be found due to the role of at least three factors operating more or less independently; the stability of the mixing line, the entrainment speed, and the strength of the internal boundary-layer circulation.

  18. Timescales of Massive Human Entrainment

    PubMed Central

    Fusaroli, Riccardo; Perlman, Marcus; Mislove, Alan; Paxton, Alexandra; Matlock, Teenie; Dale, Rick

    2015-01-01

    The past two decades have seen an upsurge of interest in the collective behaviors of complex systems composed of many agents entrained to each other and to external events. In this paper, we extend the concept of entrainment to the dynamics of human collective attention. We conducted a detailed investigation of the unfolding of human entrainment—as expressed by the content and patterns of hundreds of thousands of messages on Twitter—during the 2012 US presidential debates. By time-locking these data sources, we quantify the impact of the unfolding debate on human attention at three time scales. We show that collective social behavior covaries second-by-second to the interactional dynamics of the debates: A candidate speaking induces rapid increases in mentions of his name on social media and decreases in mentions of the other candidate. Moreover, interruptions by an interlocutor increase the attention received. We also highlight a distinct time scale for the impact of salient content during the debates: Across well-known remarks in each debate, mentions in social media start within 5–10 seconds after it occurs; peak at approximately one minute; and slowly decay in a consistent fashion across well-known events during the debates. Finally, we show that public attention after an initial burst slowly decays through the course of the debates. Thus we demonstrate that large-scale human entrainment may hold across a number of distinct scales, in an exquisitely time-locked fashion. The methods and results pave the way for careful study of the dynamics and mechanisms of large-scale human entrainment. PMID:25880357

  19. Entrainment in electrohydrodynamic heat pipes

    NASA Technical Reports Server (NTRS)

    Jones, T. B.; Perry, M. P.

    1972-01-01

    A theoretical analysis for predicting the onset of the Kelvin-Helmholtz instability is reported. The model for the analysis is described, and the derived stability criterion are given. It is concluded that surface tension plays a role in the entrainment limit of electro hydrodynamic heat pipes. The surface of the liquid in an EHD flow structure is open, with no restriction placed on the wavenumbers of perturbations.

  20. CONVERTING PYROLYSIS OILS TO RENEWABLE TRANSPORT FUELS: PROCESSING CHALLENGES & OPPORTUNITIES

    SciTech Connect

    Holmgren, Jennifer; Nair, Prabhakar N.; Elliott, Douglas C.; Bain, Richard; Marinangelli, Richard

    2008-03-11

    To enable a sustained supply of biomass-based transportation fuels, the capability to process feedstocks outside the food chain must be developed. Significant industry efforts are underway to develop these new technologies, such as converting cellulosic wastes to ethanol. UOP, in partnership with U.S. Government labs, NREL and PNNL, is developing an alternate route using cellulosic feedstocks. The waste biomass is first subjected to a fast pyrolysis operation to generate pyrolysis oil (pyoil for short). Current efforts are focused on developing a thermochemical platform to convert pyoils to renewable gasoline, diesel and jet fuel. The fuels produced will be indistinguishable from their fossil fuel counterparts and, therefore, will be compatible with existing transport and distribution infrastructure.

  1. Processing of carbon composite paper as electrode for fuel cell

    NASA Astrophysics Data System (ADS)

    Mathur, R. B.; Maheshwari, Priyanka H.; Dhami, T. L.; Sharma, R. K.; Sharma, C. P.

    The porous carbon electrode in a fuel cell not only acts as an electrolyte and a catalyst support, but also allows the diffusion of hydrogen fuel through its fine porosity and serves as a current-carrying conductor. A suitable carbon paper electrode is developed and possesses the characteristics of high porosity, permeability and strength along with low electrical resistivity so that it can be effectively used in proton-exchange membrane and phosphoric acid fuel cells. The electrode is prepared through a combination of two important techniques, viz., paper-making technology by first forming a porous chopped carbon fibre preform, and composite technology using a thermosetting resin matrix. The study reveals an interdependence of one parameter on another and how judicious choice of the processing conditions are necessary to achieve the desired characteristics. The current-voltage performance of the electrode in a unit fuel cell matches that of a commercially-available material.

  2. Motor fuel alkylation process utilizing low acid

    SciTech Connect

    Kocal, J.A.; Imai, T.

    1987-01-06

    A process is described for the alkylation of an isoparaffin with an olefin acting agent comprising contacting the isoparaffin with the olefin acting agent at alkylation conditions in the presence of a catalyst. The catalyst consists essentially of an anhydrous, nonalcoholic mixture of from about 5 to 15 wt. % methyl tert-butyl ether and from 85 to 95 wt. % hydrofluoric acid. The volumetric ratio of hydrofluoric acid to isoparaffin and olefin acting agent is less than 0.75.

  3. Processing waste fats into a fuel oil substitute

    SciTech Connect

    Pudel, F.; Lengenfeld, P.

    1993-12-31

    Waste fats have a high energy potential. They also contain impurities. For example, fats used for deep-frying contain high contents of solids, water, and chlorides. The process described in this paper removes the impurities by simple processing such as screening, washing, separating, drying, and filtering. The final quality of processed fat allows its use as a fuel oil substitute, and also as a raw material for chemical production.

  4. Pyrolysis process for producing fuel gas

    NASA Technical Reports Server (NTRS)

    Serio, Michael A. (Inventor); Kroo, Erik (Inventor); Wojtowicz, Marek A. (Inventor); Suuberg, Eric M. (Inventor)

    2007-01-01

    Solid waste resource recovery in space is effected by pyrolysis processing, to produce light gases as the main products (CH.sub.4, H.sub.2, CO.sub.2, CO, H.sub.2O, NH.sub.3) and a reactive carbon-rich char as the main byproduct. Significant amounts of liquid products are formed under less severe pyrolysis conditions, and are cracked almost completely to gases as the temperature is raised. A primary pyrolysis model for the composite mixture is based on an existing model for whole biomass materials, and an artificial neural network models the changes in gas composition with the severity of pyrolysis conditions.

  5. Product Characterization for Entrained Flow Coal/Biomass Co-Gasification

    SciTech Connect

    Maghzi, Shawn; Subramanian, Ramanathan; Rizeq, George; Singh, Surinder; McDermott, John; Eiteneer, Boris; Ladd, David; Vazquez, Arturo; Anderson, Denise; Bates, Noel

    2011-09-30

    The U.S. Department of Energy‘s National Energy Technology Laboratory (DOE NETL) is exploring affordable technologies and processes to convert domestic coal and biomass resources to high-quality liquid hydrocarbon fuels. This interest is primarily motivated by the need to increase energy security and reduce greenhouse gas emissions in the United States. Gasification technologies represent clean, flexible and efficient conversion pathways to utilize coal and biomass resources. Substantial experience and knowledge had been developed worldwide on gasification of either coal or biomass. However, reliable data on effects of blending various biomass fuels with coal during gasification process and resulting syngas composition are lacking. In this project, GE Global Research performed a complete characterization of the gas, liquid and solid products that result from the co-gasification of coal/biomass mixtures. This work was performed using a bench-scale gasifier (BSG) and a pilot-scale entrained flow gasifier (EFG). This project focused on comprehensive characterization of the products from gasifying coal/biomass mixtures in a high-temperature, high-pressure entrained flow gasifier. Results from this project provide guidance on appropriate gas clean-up systems and optimization of operating parameters needed to develop and commercialize gasification technologies. GE‘s bench-scale test facility provided the bulk of high-fidelity quantitative data under temperature, heating rate, and residence time conditions closely matching those of commercial oxygen-blown entrained flow gasifiers. Energy and Environmental Research Center (EERC) pilot-scale test facility provided focused high temperature and pressure tests at entrained flow gasifier conditions. Accurate matching of syngas time-temperature history during cooling ensured that complex species interactions including homogeneous and heterogeneous processes such as particle nucleation, coagulation, surface condensation, and

  6. Product Characterization for Entrained Flow Coal/Biomass Co-Gasification

    SciTech Connect

    Maghzi, Shawn; Subramanian, Ramanathan; Rizeq, George; Singh, Surinder; McDermott, John; Eiteneer, Boris; Ladd, David; Vazquez, Arturo; Anderson, Denise; Bates, Noel

    2011-12-11

    The U.S. Department of Energy's National Energy Technology Laboratory (DOE NETL) is exploring affordable technologies and processes to convert domestic coal and biomass resources to high-quality liquid hydrocarbon fuels. This interest is primarily motivated by the need to increase energy security and reduce greenhouse gas emissions in the United States. Gasification technologies represent clean, flexible and efficient conversion pathways to utilize coal and biomass resources. Substantial experience and knowledge had been developed worldwide on gasification of either coal or biomass. However, reliable data on effects of blending various biomass fuels with coal during gasification process and resulting syngas composition are lacking. In this project, GE Global Research performed a complete characterization of the gas, liquid and solid products that result from the co-gasification of coal/biomass mixtures. This work was performed using a bench-scale gasifier (BSG) and a pilot-scale entrained flow gasifier (EFG). This project focused on comprehensive characterization of the products from gasifying coal/biomass mixtures in a high-temperature, high-pressure entrained flow gasifier. Results from this project provide guidance on appropriate gas clean-up systems and optimization of operating parameters needed to develop and commercialize gasification technologies. GE's bench-scale test facility provided the bulk of high-fidelity quantitative data under temperature, heating rate, and residence time conditions closely matching those of commercial oxygen-blown entrained flow gasifiers. Energy and Environmental Research Center (EERC) pilot-scale test facility provided focused high temperature and pressure tests at entrained flow gasifier conditions. Accurate matching of syngas time-temperature history during cooling ensured that complex species interactions including homogeneous and heterogeneous processes such as particle nucleation, coagulation, surface condensation, and gas

  7. Performance and sulfur poisoning of Ni/CeO2 impregnated La0.75Sr0.25Cr0.5Mn0.5O3-δ anode in solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Li, Yiqian; Zhang, Yaohui; Zhu, Xingbao; Wang, Zhihong; Lü, Zhe; Huang, Xiqiang; Zhou, Yongjun; Zhu, Lin; Jiang, Wei

    2015-07-01

    In this study, comparison experiments are conducted based on yttria-stabilized zirconia (YSZ) electrolyte supported single solid oxide fuel cells (SOFCs) with pure La0.75Sr0.25Cr0.5Mn0.5O3-δ (LSCrM) or Ni/CeO2 impregnated LSCrM anodes. The single cells are tested in dry H2 and H2/H2S (50 ppm) mixture, respectively. Compared with the pure LSCrM anode, the cell with Ni/CeO2 impregnated LSCrM presents a significant performance improvement when the pure H2 is fueled to the anode, and shows a good stability during a constant-current discharge testing (398 mA cm-2). When the fuel is switched to H2/H2S mixture, the cell with Ni/CeO2 impregnated LSCrM anode still shows a remarkable constant-current discharge (120 mA cm-2) performance compared with pure LSCrM anode. The Ni/CeO2 impregnation can improve the electrochemical performance of the LSCrM anode without any sacrifice of sulfur tolerance ability. The Ni/CeO2 impregnated LSCrM might be a potential anode material for solid oxide fuel cell operating in sulfur-containing fuels. The XRD and XPS results demonstrate that the anode poisoning product is composed of adsorbed sulfur, metal sulfides and sulfate radical. The mass spectrum result confirms that the poisoning mechanism involves the reaction of sulfur with anode rather than the direct reaction between H2S gas and anode.

  8. Refractive index matched suspensions as a tool for investigating entrainment by avalanches and debris flows

    NASA Astrophysics Data System (ADS)

    Bates, Belinda; Ancey, Christophe

    2015-04-01

    Geophysical gravity flows such as avalanches and debris flows are complicated mixtures of fluid and solids, often containing particle sizes of many orders of magnitude. In a debris flow, for example, the composition varies from head to tail, and from bottom to top due to particle size segregation and recirculation. In addition the solid components may have different masses and mechanical properties. For this reason, a complete understanding of substrate entrainment by this type of flow is still out of reach. A common strategy for advancing our understanding of the physics of processes like entrainment is to use a greatly simplified laboratory model of a debris flow, and take internal and bulk measurements. This idealized technique forms the basis of this study, in which a two-phase, monodisperse suspension of PMMA beads in a refractive-index matched suspending fluid flowed down a flume, encountering an entrainable region of the same suspension on the way. This study represents the first attempt of taking continuous internal velocity measurements inside a flowing, entraining model avalanche or debris flow in the laboratory. Interior PIV measurements of flow velocity were taken in the entrainable region, along with surface height measurements, to shed some light on the entrainment mechanisms and to see how the bulk flow responded. Further, some differential pressure measurements were made in the entrainable bed to see if pore-pressure peaks had any correlation with significant events during entrainment. We present our preliminary findings and discuss the suitability of the method to entrainment investigations.

  9. A new family of Ce-doped SmFeO3 perovskite for application in symmetrical solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Fan, Weiwei; Sun, Zhu; Wang, Junkai; Zhou, Jun; Wu, Kai; Cheng, Yonghong

    2016-04-01

    Here, a nanoporous Sm0.95Ce0.05FeO3-δ (SCFO) perovskite-type oxide is assessed in regard to its possible use as an electrode material for symmetrical solid oxide fuel cells. It is found that SCFO has a good redox stability after characterizing the sample which is calcined at 850 °C in 5% H2/N2 for 10 h. Optimized electrochemical performances are obtained in both the nanoporous anode and cathode which are mainly due to the high catalytic activity of SCFO for redox reaction. The peak power density of SCFO|YSZ|SCFO symmetrical cell is as high as 130 mW cm-2 at 800 °C using pure, humidified H2 as the fuel. Moreover, the maximum power density of 193 mW cm-2 can be obtained for the SCFO:YSZ(7:3)|YSZ|SCFO:YSZ(7:3) symmetrical cell under the same conditions.

  10. On robustness of phase resetting to cell division under entrainment.

    PubMed

    Ahmed, Hafiz; Ushirobira, Rosane; Efimov, Denis

    2015-12-21

    The problem of phase synchronization for a population of genetic oscillators (circadian clocks, synthetic oscillators, etc.) is considered in this paper, taking into account a cell division process and a common entrainment input in the population. The proposed analysis approach is based on the Phase Response Curve (PRC) model of an oscillator (the first order reduced model obtained for the linearized system and inputs with infinitesimal amplitude). The occurrence of cell division introduces state resetting in the model, placing it in the class of hybrid systems. It is shown that without common entraining input in all oscillators, the cell division acts as a disturbance causing phase drift, while the presence of entrainment guarantees boundedness of synchronization phase errors in the population. The performance of the obtained solutions is demonstrated via computer experiments for two different models of circadian/genetic oscillators (Neurospora׳s circadian oscillation model and the repressilator). PMID:26463679

  11. Observing of entrainment using small UAS

    NASA Astrophysics Data System (ADS)

    Martin, S.; Bange, J.; Beyrich, F.

    2012-04-01

    Entrainment processes between the atmospheric boundary layer and the free atmosphere are important concerning vertical exchange of momentum, energy, water vapor, trace gases and aerosol. The transition zone between the convectively mixed boundary layer and the stably stratified free atmosphere is called the entrainment zone (EZ). The EZ restrains the domain of turbulence by a temperature inversion and acts as a lid to pollutants. Measurement flights of the mini meteorological aerial vehicle (M2AV) of the Technische Universität Braunschweig were performed in spring 2011 to determine the capability of the unmanned aerial system (UAS) to measure the structure of the EZ. The campaign took place at the Meteorological Observatory Lindenberg / Richard-Aßmann-Observatory of the German Meteorological Service, which is located close to Berlin. Besides the M2AV flights, standard observations were performed by a 12 m and 99 m tower, a sodar, ceilometer and radiosondes. A tethered balloon with measurement units at six different levels was operated especially for this campaign. The measurements of these systems were used to determine the inversion layer and to capture its diurnal cycle. The talk will be focused on vertical profiles of the M2AV up to the free atmosphere, detailed analysis of spatial series of w'θ' at different altitudes and on vertical profiles of normalized variances of the vertical wind component and the potential temperature.

  12. FUEL ETHANOL PRODUCTION FROM AGRICULTURAL RESIDUES AND PROCESSING BYPRODUCTS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In 2005, the production of fuel ethanol from corn starch reached 4.5 billion gallons in the U.S. Various agricultural residues such as corn stover and wheat straw, and agricultural processing byproducts such as corn fiber and rice hulls, can serve as low-cost lignocellulosic feedstocks for conversi...

  13. Fuel ethanol production from crop residues and processing byproducts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In 2007, the production of fuel ethanol from corn starch reached 6.5 billion gallons in the U.S.A. Various crop residues such as corn stover, wheat straw, and barley straw, and crop processing byproducts such as corn fiber and rice hulls can serve as low-cost lignocellulosic feedstocks for conversi...

  14. 76 FR 44049 - Guidance for Fuel Cycle Facility Change Processes

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-22

    ... COMMISSION Guidance for Fuel Cycle Facility Change Processes AGENCY: Nuclear Regulatory Commission. ACTION: Draft regulatory guide; extension of comment period. SUMMARY: On July 14, 2011 (76 FR 41527), the U.S...: Richard.Jervey@nrc.gov . SUPPLEMENTARY INFORMATION: On July 14, 2011 (76 FR 41527), the NRC published...

  15. PROCESS OF DISSOLVING FUEL ELEMENTS OF NUCLEAR REACTORS

    DOEpatents

    Wall, E.M.V.; Bauer, D.T.; Hahn, H.T.

    1963-09-01

    A process is described for dissolving stainless-steelor zirconium-clad uranium dioxide fuel elements by immersing the elements in molten lead chloride, adding copper, cuprous chloride, or cupric chloride as a catalyst and passing chlorine through the salt mixture. (AEC)

  16. Fate of virginiamycin through the fuel ethanol production process

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Antibiotics are frequently used to prevent and treat bacterial contamination of commercial fuel ethanol fermentations, but there is concern that antibiotic residues may persist in the distillers grains coproducts. A study to evaluate the fate of virginiamycin during the ethanol production process wa...

  17. Method For Processing Spent (Trn,Zr)N Fuel

    DOEpatents

    Miller, William E.; Richmann, Michael K.

    2004-07-27

    A new process for recycling spent nuclear fuels, in particular, mixed nitrides of transuranic elements and zirconium. The process consists of two electrorefiner cells in series configuration. A transuranic element such as plutonium is reduced at the cathode in the first cell, zirconium at the cathode in the second cell, and nitrogen-15 is released and captured for reuse to make transuranic and zirconium nitrides.

  18. Holes and Entrainment in Stratocumulus.

    NASA Astrophysics Data System (ADS)

    Gerber, H.; Frick, G.; Malinowski, S. P.; Brenguier, J.-L.; Burnet, F.

    2005-02-01

    Aircraft flights through stratocumulus clouds (Sc) during the Dynamics and Chemistry of Marine Stratocumulus II (DYCOMS-II) study off the California coast found narrow in-cloud regions with less liquid water content (LWC) and cooler temperatures than average background values. The regions are named cloud holes and are assumed to be a result of water evaporated by the entrainment of dryer air from above the Sc. While such features have been noted previously, this study provided a unique opportunity to investigate in much greater detail the nature of the holes, as well as their relationship to the entrainment rate, because high-speed temperature and LWC probes with maximum spatial resolution of 10 cm were flown together for the first time. Nine long-duration flights were made through mostly unbroken Sc for which conditional sampling was used to identify the location and size of the holes. The holes are concentrated near cloud top, their average width near cloud top is about 5 m, their relative length distribution is nearly constant for all flights, and they can penetrate hundreds of meters deep into the Sc before being lost by mixing. Entrainment velocities at cloud top are estimated from measurements of fluxes of reduced LWC and vapor mixing ratios in holes, the fraction of cloud area covered by holes, and the total water jump between cloud top and the free atmosphere. Rates as large as 10 mm s-1 are found for nocturnal flights, and these rates are about 3 times larger than for daytime flight segments. The rates correlate best with the size of the buoyancy jump above the Sc; the present conditional-sampling approach for measuring the rates gives larger rates than the "flux jump" rates determined by others for the same flights by a factor of about 2. The stability criterion for all Sc predicts thinning and breakup of the Sc, which does not occur. The minimal amount of cloud-top evaporative cooling caused by entrainment contributes little to the top-down convection

  19. Crustal entrainment and pulsar glitches.

    PubMed

    Chamel, N

    2013-01-01

    Large pulsar frequency glitches are generally interpreted as sudden transfers of angular momentum between the neutron superfluid permeating the inner crust and the rest of the star. Despite the absence of viscous drag, the neutron superfluid is strongly coupled to the crust due to nondissipative entrainment effects. These effects are shown to severely limit the maximum amount of angular momentum that can possibly be transferred during glitches. In particular, it is found that the glitches observed in the Vela pulsar require an additional reservoir of angular momentum. PMID:23383772

  20. The Stochastic Parcel Model: A deterministic parameterization of stochastically entraining convection

    NASA Astrophysics Data System (ADS)

    Romps, David M.

    2016-03-01

    Convective entrainment is a process that is poorly represented in existing convective parameterizations. By many estimates, convective entrainment is the leading source of error in global climate models. As a potential remedy, an Eulerian implementation of the Stochastic Parcel Model (SPM) is presented here as a convective parameterization that treats entrainment in a physically realistic and computationally efficient way. Drawing on evidence that convecting clouds comprise air parcels subject to Poisson-process entrainment events, the SPM calculates the deterministic limit of an infinite number of such parcels. For computational efficiency, the SPM groups parcels at each height by their purity, which is a measure of their total entrainment up to that height. This reduces the calculation of convective fluxes to a sequence of matrix multiplications. The SPM is implemented in a single-column model and compared with a large-eddy simulation of deep convection.

  1. Process gases for high velocity oxy-fuel thermal spraying

    SciTech Connect

    Creffield, G.K.; Chapman, I.F.; Cole, M.A.; Page, W.J.; McDonough, T.

    1994-12-31

    The importance of fuel and other process gases for high velocity oxy-fuel (HVOF) thermal spraying and especially the delivery of them to the point of use is well recognized. Problems associated with the supply of liquid fuel gases, at the high flow rates and pressures required by this process, have been addressed. Considerable development work has gone into designing an appropriate liquid withdrawal and vaporizer system for propylene, which overcomes these previous difficulties and enables users to maintain adequate fuel gas flow rates in order to ensure optimum operating conditions for the production of high quality coatings. A feature of the thermal spray process is that the temperature of the workpiece is kept low, typically below 150 C, in order to reduce residual stresses in the coating and to protect heat sensitive substrates. Traditionally this has been by compressed air, however, improved cooling has been achieved using carbon dioxide. Specially designed equipment is now available which provides and directs a cold mixture of carbon dioxide gas and solid particles (snow) via suitable nozzles, on the workpiece. The position of the cooling stream can be varied, depending on the application. These developments emphasize the importance now attached to providing dedicated gas installation packages for HVOF.

  2. Optimal entrainment of heterogeneous noisy neurons

    PubMed Central

    Wilson, Dan; Holt, Abbey B.; Netoff, Theoden I.; Moehlis, Jeff

    2015-01-01

    We develop a methodology to design a stimulus optimized to entrain nonlinear, noisy limit cycle oscillators with uncertain properties. Conditions are derived which guarantee that the stimulus will entrain the oscillators despite these uncertainties. Using these conditions, we develop an energy optimal control strategy to design an efficient entraining stimulus and apply it to numerical models of noisy phase oscillators and to in vitro hippocampal neurons. In both instances, the optimal stimuli outperform other similar but suboptimal entraining stimuli. Because this control strategy explicitly accounts for both noise and inherent uncertainty of model parameters, it could have experimental relevance to neural circuits where robust spike timing plays an important role. PMID:26074762

  3. Used nuclear fuel separations process simulation and testing

    SciTech Connect

    Pereira, C.; Krebs, J.F.; Copple, J.M.; Frey, K.E.; Maggos, L.E.; Figueroa, J.; Willit, J.L.; Papadias, D.D.

    2013-07-01

    Recent efforts in separations process simulation at Argonne have expanded from the traditional focus on solvent extraction flowsheet design in order to capture process dynamics and to simulate other components, processing and systems of a used nuclear fuel reprocessing plant. For example, the Argonne Model for Universal Solvent Extraction (AMUSE) code has been enhanced to make it both more portable and more readily extensible. Moving away from a spreadsheet environment makes the addition of new species and processes simpler for the expert user, which should enable more rapid implementation of chemical models that simulate evolving processes. The dyAMUSE (dynamic AMUSE) version allows the simulation of transient behavior across an extractor. Electrochemical separations have now been modeled using spreadsheet codes that simulate the electrochemical recycle of fast reactor fuel. The user can follow the evolution of the salt, products, and waste compositions in the electro-refiner, cathode processors, and drawdown as a function of fuel batches treated. To further expand capabilities in integrating multiple unit operations, a platform for linking mathematical models representing the different operations that comprise a reprocessing facility was adapted to enable systems-level analysis and optimization of facility functions. (authors)

  4. Coal liquefaction process wherein jet fuel, diesel fuel and/or ASTM No. 2 fuel oil is recovered

    DOEpatents

    Bauman, Richard F.; Ryan, Daniel F.

    1982-01-01

    An improved process for the liquefaction of coal and similar solid carbonaceous materials wherein a hydrogen donor solvent or diluent derived from the solid carbonaceous material is used to form a slurry of the solid carbonaceous material and wherein the naphthenic components from the solvent or diluent fraction are separated and used as jet fuel components. The extraction increases the relative concentration of hydroaromatic (hydrogen donor) components and as a result reduces the gas yield during liquefaction and decreases hydrogen consumption during said liquefaction. The hydrogenation severity can be controlled to increase the yield of naphthenic components and hence the yield of jet fuel and in a preferred embodiment jet fuel yield is maximized while at the same time maintaining solvent balance.

  5. Fuel processing for PEM fuel cells: transport and kinetic issues of system design

    NASA Astrophysics Data System (ADS)

    Zalc, J. M.; Löffler, D. G.

    In light of the distribution and storage issues associated with hydrogen, efficient on-board fuel processing will be a significant factor in the implementation of PEM fuel cells for automotive applications. Here, we apply basic chemical engineering principles to gain insight into the factors that limit performance in each component of a fuel processor. A system consisting of a plate reactor steam reformer, water-gas shift unit, and preferential oxidation reactor is used as a case study. It is found that for a steam reformer based on catalyst-coated foils, mass transfer from the bulk gas to the catalyst surface is the limiting process. The water-gas shift reactor is expected to be the largest component of the fuel processor and is limited by intrinsic catalyst activity, while a successful preferential oxidation unit depends on strict temperature control in order to minimize parasitic hydrogen oxidation. This stepwise approach of sequentially eliminating rate-limiting processes can be used to identify possible means of performance enhancement in a broad range of applications.

  6. Analysis of on-board fuel processing designs for PEM fuel cell vehicles

    SciTech Connect

    Kartha, S.; Fischer, S.; Kreutz, T.

    1996-12-31

    As a liquid fuel with weight and volume energy densities comparable to those of gasoline, methanol is an attractive energy carrier for mobile power systems. It is available without contaminants such as sulfur, and can be easily reformed at relatively low temperatures with inexpensive catalysts. This study is concerned with comparing the net efficiencies of PEM fuel cell vehicles fueled with methanol and hydrogen, using fuel cell system models developed using ASPEN chemical process simulation software. For both the methanol and hydrogen systems, base case designs are developed and several variations are considered that differ with respect to the degree of system integration for recovery of heat and compressive work. The methanol systems are based on steam reforming with the water-gas shift reaction and preferential oxidation, and the hydrogen systems are based on compressed hydrogen. This analysis is an exercise in optimizing the system design for each fuel, which ultimately entails balancing system efficiency against a host of other considerations, including system complexity, performance, cost, reliability, weight and volume.

  7. Scalar entrainment in the mixing layer

    NASA Technical Reports Server (NTRS)

    Sandham, N. D.; Mungal, M. G.; Broadwell, J. E.; Reynolds, W. C.

    1988-01-01

    New definitions of entrainment and mixing based on the passive scalar field in the plane mixing layer are proposed. The definitions distinguish clearly between three fluid states: (1) unmixed fluid, (2) fluid engulfed in the mixing layer, trapped between two scalar contours, and (3) mixed fluid. The difference betwen (2) and (3) is the amount of fluid which has been engulfed during the pairing process, but has not yet mixed. Trends are identified from direct numerical simulations and extensions to high Reynolds number mixing layers are made in terms of the Broadwell-Breidenthal mixing model. In the limit of high Peclet number (Pe = ReSc) it is speculated that engulfed fluid rises in steps associated with pairings, introducing unmixed fluid into the large scale structures, where it is eventually mixed at the Kolmogorov scale. From this viewpoint, pairing is a prerequisite for mixing in the turbulent plane mixing layer.

  8. Investigation of GdBaCo2-xFexO6-δ (x = 0, 0.2) - Ce0.8Sm0.2O2 composite cathodes for intermediate temperature solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Tsvetkova, N. S.; Zuev, A. Yu.; Tsvetkov, D. S.

    2013-12-01

    The double perovskites GdBaCo2-xFexO6-δ (x = 0, 0.2) and composites (100 - y) GdBaCo2-xFexO6-δ (x = 0, 0.2) - y Ce0.8Sm0.2O2 (y = 10-50 wt.%) were investigated as cathode materials for intermediate temperature solid oxide fuel cells (IT-SOFCs). Chemical compatibility of GdBaCo2-xFexO6-δ (x = 0, 0.2) with solid electrolyte Ce0.8Sm0.2O2, thermal expansion, DC conductivity and electrochemical performance of (100 - y) GdBaCo2-xFexO6-δ (x = 0, 0.2) - y Ce0.8Sm0.2O2 (y = 10-50 wt.%) were studied. Partial substitution of Fe for Co was shown to lead to decrease of double perovskite GdBaCo2-xFexO6-δ reactivity with the solid electrolyte Ce0.8Sm0.2O2. Polarization resistance of cathodes studied was found to depend significantly on firing temperature. Variation of solid electrolyte content in (100 - y) GdBaCo2-xFexO6-δ (x = 0, 0.2) - y Ce0.8Sm0.2O2 (y = 10-50 wt.%) composites was shown to allow to optimize their electrochemical performance. Cathode materials of 80 wt.% GdBaCo2O6-δ - 20 wt.% Ce0.8Sm0.2O2 and 65 wt.% GdBaCo1.8Fe0.2O6-δ - 35 wt.% Ce0.8Sm0.2O2 were found to have the lowest polarization resistances and reasonable values of thermal expansion coefficient (TEC) and, therefore, can be considered as promising cathode materials for IT-SOFCs.

  9. Characteristics of air entrainment during dynamic wetting failure along a planar substrate

    NASA Astrophysics Data System (ADS)

    Kumar, Satish; Vandre, Eric; Carvalho, Marcio

    2014-11-01

    We report results of experiments characterizing the onset of air entrainment during dynamic wetting failure along a planar substrate (J. Fluid Mech. 747, 119 (2014)). Using high-speed video, dynamic contact line (DCL) behavior is recorded as a tape substrate is drawn through a bath of a glycerol/water solution. Air entrainment is identified by triangular air films that elongate from the DCL above a critical substrate speed. Meniscus confinement between the substrate and a stationary plate delays air entrainment to higher speeds for a wide range of liquid viscosities. Liquid pressurization moves the meniscus near a sharp corner, changing its shape and further postponing air entrainment. Meniscus shapes recorded near the DCL demonstrate that smaller entrained air films appear in the more viscous solutions. Regardless of size, air films become unstable to thickness perturbations and ultimately rupture, leading to entrainment of air bubbles. Recorded critical speeds and air-film sizes compare well to predictions from a hydrodynamic model for dynamic wetting failure, indicating that strong air stresses near the DCL trigger the onset of air entrainment. The results suggest strategies for postponing air entrainment, which often limits the maximum speed of industrial coating processes.

  10. Process development and fabrication for sphere-pac fuel rods. [PWR; BWR

    SciTech Connect

    Welty, R.K.; Campbell, M.H.

    1981-06-01

    Uranium fuel rods containing sphere-pac fuel have been fabricated for in-reactor tests and demonstrations. A process for the development, qualification, and fabrication of acceptable sphere-pac fuel rods is described. Special equipment to control fuel contamination with moisture or air and the equipment layout needed for rod fabrication is described and tests for assuring the uniformity of the fuel column are discussed. Fuel retainers required for sphere-pac fuel column stability and instrumentation to measure fuel column smear density are described. Results of sphere-pac fuel rod fabrication campaigns are reviewed and recommended improvements for high throughput production are noted.

  11. FUEL ELEMENTS FOR NUCLEAR REACTORS AND PROCESS OF MAKING

    DOEpatents

    Roake, W.E.

    1958-08-19

    A process is described for producing uranium metal granules for use in reactor fuel elements. The granules are made by suspending powdered uramiunn metal or uranium hydride in a viscous, non-reactive liquid, such as paraffin oil, aad pouring the resulting suspension in droplet, on to a bed of powdered absorbent. In this manner the liquid vehicle is taken up by the sorbent and spherical pellets of uranium metal are obtained. The

  12. Femtosecond laser processing of fuel injectors - a materials processing evaluation

    SciTech Connect

    Stuart, B C; Wynne, A

    2000-12-16

    Lawrence Livermore National Laboratory (LLNL) has developed a new laser-based machining technology that utilizes ultrashort-pulse (0.1-1.0 picosecond) lasers to cut materials with negligible generation of heat or shock. The ultrashort pulse laser, developed for the Department of Energy (Defense Programs) has numerous applications in operations requiring high precision machining. Due to the extremely short duration of the laser pulse, material removal occurs by a different physical mechanism than in conventional machining. As a result, any material (e.g., hardened steel, ceramics, diamond, silicon, etc.) can be machined with minimal heat-affected zone or damage to the remaining material. As a result of the threshold nature of the process, shaped holes, cuts, and textures can be achieved with simple beam shaping. Conventional laser tools used for cutting or high-precision machining (e.g., sculpting, drilling) use long laser pulses (10{sup -8} to over 1 sec) to remove material by heating it to the melting or boiling point (Figure 1.1a). This often results in significant damage to the remaining material and produces considerable slag (Figure 1.2a). With ultrashort laser pulses, material is removed by ionizing the material (Figure 1.1b). The ionized plasma expands away from the surface too quickly for significant energy transfer to the remaining material. This distinct mechanism produces extremely precise and clean-edged holes without melting or degrading the remaining material (Figures 1.2 and 1.3). Since only a very small amount of material ({approx} <0.5 microns) is removed per laser pulse, extremely precise machining can be achieved. High machining speed is achieved by operating the lasers at repetition rates up to 10,000 pulses per second. As a diagnostic, the character of the short-pulse laser produced plasma enables determination of the material being machined between pulses. This feature allows the machining of multilayer materials, metal on metal or metal on

  13. Modular, High-Volume Fuel Cell Leak-Test Suite and Process

    SciTech Connect

    Ru Chen; Ian Kaye

    2012-03-12

    Fuel cell stacks are typically hand-assembled and tested. As a result the manufacturing process is labor-intensive and time-consuming. The fluid leakage in fuel cell stacks may reduce fuel cell performance, damage fuel cell stack, or even cause fire and become a safety hazard. Leak check is a critical step in the fuel cell stack manufacturing. The fuel cell industry is in need of fuel cell leak-test processes and equipment that is automatic, robust, and high throughput. The equipment should reduce fuel cell manufacturing cost.

  14. Laboratory experiments on stability and entrainment of oceanic stratocumulus. Part 2: Entrainment experiment

    NASA Technical Reports Server (NTRS)

    Shy, Shenqyang S.

    1990-01-01

    A stratified interface is stable to the buoyancy reversal instability for surprisingly large values of D (buoyancy reversal parameter). A new instability mechanism is proposed, which considers the mixing process at the interface. For the type of density curves studied here, under strong perturbations, the mixed parcel must have a buoyancy reversal comparable to the initial stratification before the interface is unstable. This is in accord with a simple model of the interface mixing process, as well as aircraft observations of long-live marine stratocumulus clouds. These clouds' remarkable longevity in the face of finite D indicates that they can be stable (Hanson, 1984; Albrecht et al., 1985; Siems et al., 1989). It is suggested that buoyancy reversal as well as the disturbance must be large for Cloudtop Entrainment Stability. The effect of buoyancy reversal (evaporative cooling) does not always enhance the entrainment rate over that in the inert case, but it may be negligible if Ri (Richardson number) is large (Ri is larger than 50) and D is small (D is smaller than 0.5). This work may shed some light on the fundamental mechanism of the breakup process of the subtropical stratocumulus clouds into tradewind cumulus. These results may also be related to the instability in the Weddell Sea off of Antarctica.

  15. Understanding the transport processes in polymer electrolyte membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Cheah, May Jean

    Polymer electrolyte membrane (PEM) fuel cells are energy conversion devices suitable for automotive, stationary and portable applications. An engineering challenge that is hindering the widespread use of PEM fuel cells is the water management issue, where either a lack of water (resulting in membrane dehydration) or an excess accumulation of liquid water (resulting in fuel cell flooding) critically reduces the PEM fuel cell performance. The water management issue is addressed by this dissertation through the study of three transport processes occurring in PEM fuel cells. Water transport within the membrane is a combination of water diffusion down the water activity gradient and the dragging of water molecules by protons when there is a proton current, in a phenomenon termed electro-osmotic drag, EOD. The impact of water diffusion and EOD on the water flux across the membrane is reduced due to water transport resistance at the vapor/membrane interface. The redistribution of water inside the membrane by EOD causes an overall increase in the membrane resistance that regulates the current and thus EOD, thereby preventing membrane dehydration. Liquid water transport in the PEM fuel cell flow channel was examined at different gas flow regimes. At low gas Reynolds numbers, drops transitioned into slugs that are subsequently pushed out of the flow channel by the gas flow. The slug volume is dependent on the geometric shape, the surface wettability and the orientation (with respect to gravity) of the flow channel. The differential pressure required for slug motion primarily depends on the interfacial forces acting along the contact lines at the front and the back of the slug. At high gas Reynolds number, water is removed as a film or as drops depending on the flow channel surface wettability. The shape of growing drops at low and high Reynolds number can be described by a simple interfacial energy minimization model. Under flooding conditions, the fuel cell local current

  16. Integration and testing of hot desulfurization and entrained-flow gasification for power generation systems. Phase 2, Process optimization: Volume 1, Program summary and PDU operations

    SciTech Connect

    Robin, A.M.; Kassman, J.S.; Leininger, T.F.; Wolfenbarger, J.K.; Wu, C.M.; Yang, P.P.

    1991-09-01

    This second Topical Report describes the work that was completed between January 1, 1989 and December 31, 1990 in a Cooperative Agreement between Texaco and the US Department of Energy that began on September 30, 1987. During the period that is covered in this report, the development and optimization of in-situ and external desulfurization processes were pursued. The research effort included bench scale testing, PDU scoping tests, process economic studies and advanced instrument testing. Two bench scale studies were performed at the Research Triangle Institute with zinc titanate sorbent to obtain data on its cycle life, sulfur capacity, durability and the effect of chlorides. These studies quantify sulfur capture during simulated air and oxygen-blown gasification for two zinc titanate formulations. Eight PDU runs for a total of 20 days of operation were conducted to evaluate the performance of candidate sorbents for both in-situ and external desulfurization. A total of 47 tests were completed with oxygen and air-blown gasification. Candidate sorbents included iron oxide for in-situ desulfurization and calcium based and mixed metal oxides for external desulfurization. Gasifier performance and sorbent sulfur capture are compared for both air-blown and oxygen-blown operation.

  17. Process for converting cellulosic materials into fuels and chemicals

    DOEpatents

    Scott, Charles D.; Faison, Brendlyn D.; Davison, Brian H.; Woodward, Jonathan

    1994-01-01

    A process for converting cellulosic materials, such as waste paper, into fuels and chemicals utilizing enzymatic hydrolysis of the major constituent of paper, cellulose. A waste paper slurry is contacted by cellulase in an agitated hydrolyzer. The cellulase is produced from a continuous, columnar, fluidized-bed bioreactor utilizing immobilized microorganisms. An attritor and a cellobiase reactor are coupled to the agitated hydrolyzer to improve reaction efficiency. The cellulase is recycled by an adsorption process. The resulting crude sugars are converted to dilute product in a fluidized-bed bioreactor utilizing microorganisms. The dilute product is concentrated and purified by utilizing distillation and/or a biparticle fluidized-bed bioreactor system.

  18. Scale dependence of entrainment-mixing mechanisms in cumulus clouds

    DOE PAGESBeta

    Lu, Chunsong; Liu, Yangang; Niu, Shengjie; Endo, Satoshi

    2014-12-17

    This work empirically examines the dependence of entrainment-mixing mechanisms on the averaging scale in cumulus clouds using in situ aircraft observations during the Routine Atmospheric Radiation Measurement Aerial Facility Clouds with Low Optical Water Depths Optical Radiative Observations (RACORO) field campaign. A new measure of homogeneous mixing degree is defined that can encompass all types of mixing mechanisms. Analysis of the dependence of the homogenous mixing degree on the averaging scale shows that, on average, the homogenous mixing degree decreases with increasing averaging scales, suggesting that apparent mixing mechanisms gradually approach from homogeneous mixing to extreme inhomogeneous mixing with increasingmore » scales. The scale dependence can be well quantified by an exponential function, providing first attempt at developing a scale-dependent parameterization for the entrainment-mixing mechanism. The influences of three factors on the scale dependence are further examined: droplet-free filament properties (size and fraction), microphysical properties (mean volume radius and liquid water content of cloud droplet size distributions adjacent to droplet-free filaments), and relative humidity of entrained dry air. It is found that the decreasing rate of homogeneous mixing degree with increasing averaging scales becomes larger with larger droplet-free filament size and fraction, larger mean volume radius and liquid water content, or higher relative humidity. The results underscore the necessity and possibility of considering averaging scale in representation of entrainment-mixing processes in atmospheric models.« less

  19. Scale dependence of entrainment-mixing mechanisms in cumulus clouds

    SciTech Connect

    Lu, Chunsong; Liu, Yangang; Niu, Shengjie; Endo, Satoshi

    2014-12-17

    This work empirically examines the dependence of entrainment-mixing mechanisms on the averaging scale in cumulus clouds using in situ aircraft observations during the Routine Atmospheric Radiation Measurement Aerial Facility Clouds with Low Optical Water Depths Optical Radiative Observations (RACORO) field campaign. A new measure of homogeneous mixing degree is defined that can encompass all types of mixing mechanisms. Analysis of the dependence of the homogenous mixing degree on the averaging scale shows that, on average, the homogenous mixing degree decreases with increasing averaging scales, suggesting that apparent mixing mechanisms gradually approach from homogeneous mixing to extreme inhomogeneous mixing with increasing scales. The scale dependence can be well quantified by an exponential function, providing first attempt at developing a scale-dependent parameterization for the entrainment-mixing mechanism. The influences of three factors on the scale dependence are further examined: droplet-free filament properties (size and fraction), microphysical properties (mean volume radius and liquid water content of cloud droplet size distributions adjacent to droplet-free filaments), and relative humidity of entrained dry air. It is found that the decreasing rate of homogeneous mixing degree with increasing averaging scales becomes larger with larger droplet-free filament size and fraction, larger mean volume radius and liquid water content, or higher relative humidity. The results underscore the necessity and possibility of considering averaging scale in representation of entrainment-mixing processes in atmospheric models.

  20. The neurochemical basis of photic entrainment of the circadian pacemaker

    NASA Technical Reports Server (NTRS)

    Rea, Michael A.; Buckley, Becky; Lutton, Lewis M.

    1992-01-01

    Circadian rhythmicity in mammals is controlled by the action of a light-entrainable hypothalamus, in association with two cell clusters known as the supra chiasmatic nuclei (SCN). In the absence of temporal environmental clues, this pacemaker continues to measure time by an endogenous mechanism (clock), driving biochemical, physiological, and behavioral rhythms that reflect the natural period of the pacemaker oscillation. This endogenous period usually differs slightly from 24 hours (i.e., circadian). When mammals are maintained under a 24 hour light-dark (LD) cycle, the pacemaker becomes entrained such that the period of the pacemaker oscillation matches that of the LD cycle. Potentially entraining photic information is conveyed to the SCN via a direct retinal projection, the retinohypothalamic tract (RHT). RHT neurotransmission is thought to be mediated by the release of excitatory amino acids (EAA) in the SCN. In support of this hypothesis, recent experiments using nocturnal rodents have shown that EAA antagonists block the effects of light on pacemaker-driven behavioral rhythms, and attenuate light induced gene expression in SCN cells. An understanding of the neurochemical basis of the photic entrainment process would facilitate the development of pharmacological strategies for maintaining synchrony among shift workers in environments, such as the Space Station, which provide unreliable or conflicting temporal photic clues.

  1. Process for producing fuel from plant sources and fuel blends containing same

    SciTech Connect

    Whitworth, R.D.

    1987-04-04

    A process for producing a fuel from plant sources comprising the steps of: (a) providing a supply of limonene; (b) distilling the limonene and removing the distillate fraction in a temperature range of from about 346/sup 0/F to about 382/sup 0/F; (c) removing water from the distilled limonene; and (d) treating the distilled limonene to preclude the formation of gums therefrom.

  2. Fast biomass pyrolysis with an entrained-flow reactor

    NASA Astrophysics Data System (ADS)

    Bohn, M. S.; Benham, C.

    1982-02-01

    A tubular entrained flow reactor has been used to study the effect of process control variables on fast biomass pyrolysis. In this type of reactor, finely ground biomass particles are entrained by carrier gas and transported through a reactor tube which is heated to about 900 C. Biomass particles pyrolyze as a result of heat transfer from the reactor wall yielding a gas composed primarily of carbon monoxide, carbon dioxide, hydrogen, methane, and unsaturated hydrocarbons. In this experimental program three dependent variables, percent conversion to gas, gas composition, and process heat, have been measured as a function of several process control variables. These process variables include reactor temperature, carrier gas to biomass flow ratio, reactor residence time, biomass particle size, and reactor Reynolds number. The data allow one to design and predict the performance of large scale reactors and also elucidates heat transfer mechanisms in fast biomass pyrolysis.

  3. Actinide partitioning processes for fuel reprocessing and refabrication plant wastes

    SciTech Connect

    Finney, B.C.; Tedder, D.W.

    1980-01-01

    Chemical processing methods have been developed on a laboratory scale to partition the actinides from the liquid and solid fuel reprocessing plant (FRP) and refabrication plant (FFP) wastes. It was envisioned that these processes would be incorporated into separate waste treatment facilities (WTFs) that are adjacent to, but not integrated with, the fuel reprocessing and refabrication plants. Engineering equipment and material balance flowsheets have been developed for WTFs in support of a 2000-MTHM/year FRP and a 660-MTHM/year MOX-FFP. The processing subsystems incorporated in the FRP-WTF are: High-Level Solid Waste Treatment, High-Level Liquid Waste Treatment, Solid Alpha Waste Treatment, Cation Exchange Chromatography, Salt Waste Treatment, Actinide Recovery, Solvent Cleanup and recycle, Off-Gas Treatment, Actinide Product Concentration, and Acid and Water Recycle. The WTF supporting a fuel refabrication facility, although similar, does not contain subsystems (1) and (2). Based on the results of the laboratory and hot-cell experimental work, we believe that the processes and flowsheets offer the potential to reduce the total unrecovered actinides in FRP and FFP wastes to less than or equal to 0.25%. The actinide partitioning processes and the WTF concept represent advanced technology that would require substantial work before commercialization. It is estimated that an orderly development program would require 15 to 20 years to complete and would cost about 700 million 1979 dollars. It is estimated that the capital cost and annual operating cost, in mid-1979 dollars, for the FRP-WTF are $1035 million and $71.5 million/year, and for the FFP-WTF are $436 million and $25.6 million/year, respectively.

  4. Synthesis and electrochemical characterization of Sr2Fe1.5Mo0.5O6-Sm0.2Ce0.8O1.9 composite cathode for intermediate-temperature solid oxide fuel cells

    NASA Astrophysics Data System (ADS)

    Dai, Ningning; Lou, Zhongliang; Wang, Zhenhua; Liu, Xiaoxi; Yan, Yiming; Qiao, Jinshuo; Jiang, Taizhi; Sun, Kening

    2013-12-01

    Nanoporous composite oxides Sr2Fe1.5Mo0.5O6-Sm0.2Ce0.8O1.9 (SFM-SDC) have been prepared by a facile one-step method as cathode for intermediate-temperature solid oxide fuel cells (IT-SOFCs). The SFM-SDC composite materials have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), scanning transmission electron microscopy (STEM) and electrochemical impedance spectroscopy (EIS). The EIS results exhibit that SFM-SDC40 (wt% 60:40) cathode has encouraging electrochemical performance with low polarization resistance (Rp) on YSZ (Y2O3-stabilized ZrO2) electrolyte. Subsequently, bi-layer cathodes SDC/SFM-SDC are fabricated, and excellent electrochemical performance of such composite cathodes are observed. We demonstrate that the SDC interlayer significantly decreases the Rp of cathode and accelerates the charge transfer process. As a result, the Rp of the SDC/SFM-SDC40 bi-layer cathodes is almost 50% less than that of SFM-SDC40 cathode on YSZ electrolyte at 800 °C, and Rp is only 0.11 Ω cm2. Compared with single cells without an interlayer, the anode-supported single cells with SDC interlayer exhibit enhancement in overall power performance.

  5. The performative pleasure of imprecision: a diachronic study of entrainment in music performance

    PubMed Central

    Geeves, Andrew; McIlwain, Doris J.; Sutton, John

    2014-01-01

    This study focuses in on a moment of live performance in which the entrainment amongst a musical quartet is threatened. Entrainment is asymmetric in so far as there is an ensemble leader who improvises and expands the structure of a last chorus of a piece of music beyond the limits tacitly negotiated during prior rehearsals and performances. Despite the risk of entrainment being disturbed and performance interrupted, the other three musicians in the quartet follow the leading performer and smoothly transition into unprecedented performance territory. We use this moment of live performance to work back through the fieldwork data, building a diachronic study of the development and bases of entrainment in live music performance. We introduce the concept of entrainment and profile previous theory and research relevant to entrainment in music performance. After outlining our methodology, we trace the evolution of the structure of the piece of music from first rehearsal to final performance. Using video clip analysis, interviews and field notes we consider how entrainment shaped and was shaped by the moment of performance in focus. The sense of trust between quartet musicians is established through entrainment processes, is consolidated via smooth adaptation to the threats of disruption. Non-verbal communicative exchanges, via eye contact, gesture, and spatial proximity, sustain entrainment through phase shifts occurring swiftly and on the fly in performance contexts. These exchanges permit smooth adaptation promoting trust. This frees the quartet members to play with the potential disturbance of equilibrium inherent in entrained relationships and to play with this tension in an improvisatory way that enhances audience engagement and the live quality of performance. PMID:25400567

  6. The performative pleasure of imprecision: a diachronic study of entrainment in music performance.

    PubMed

    Geeves, Andrew; McIlwain, Doris J; Sutton, John

    2014-01-01

    This study focuses in on a moment of live performance in which the entrainment amongst a musical quartet is threatened. Entrainment is asymmetric in so far as there is an ensemble leader who improvises and expands the structure of a last chorus of a piece of music beyond the limits tacitly negotiated during prior rehearsals and performances. Despite the risk of entrainment being disturbed and performance interrupted, the other three musicians in the quartet follow the leading performer and smoothly transition into unprecedented performance territory. We use this moment of live performance to work back through the fieldwork data, building a diachronic study of the development and bases of entrainment in live music performance. We introduce the concept of entrainment and profile previous theory and research relevant to entrainment in music performance. After outlining our methodology, we trace the evolution of the structure of the piece of music from first rehearsal to final performance. Using video clip analysis, interviews and field notes we consider how entrainment shaped and was shaped by the moment of performance in focus. The sense of trust between quartet musicians is established through entrainment processes, is consolidated via smooth adaptation to the threats of disruption. Non-verbal communicative exchanges, via eye contact, gesture, and spatial proximity, sustain entrainment through phase shifts occurring swiftly and on the fly in performance contexts. These exchanges permit smooth adaptation promoting trust. This frees the quartet members to play with the potential disturbance of equilibrium inherent in entrained relationships and to play with this tension in an improvisatory way that enhances audience engagement and the live quality of performance. PMID:25400567

  7. Doing Duo – a case study of entrainment in William Forsythe’s choreography “Duo”

    PubMed Central

    Waterhouse, Elizabeth; Watts, Riley; Bläsing, Bettina E.

    2014-01-01

    Entrainment theory focuses on processes in which interacting (i.e., coupled) rhythmic systems stabilize, producing synchronization in the ideal sense, and forms of phase related rhythmic coordination in complex cases. In human action, entrainment involves spatiotemporal and social aspects, characterizing the meaningful activities of music, dance, and communication. How can the phenomenon of human entrainment be meaningfully studied in complex situations such as dance? We present an in-progress case study of entrainment in William Forsythe’s choreography Duo, a duet in which coordinated rhythmic activity is achieved without an external musical beat and without touch-based interaction. Using concepts of entrainment from different disciplines as well as insight from Duo performer Riley Watts, we question definitions of entrainment in the context of dance. The functions of chorusing, turn-taking, complementary action, cues, and alignments are discussed and linked to supporting annotated video material. While Duo challenges the definition of entrainment in dance as coordinated response to an external musical or rhythmic signal, it supports the definition of entrainment as coordinated interplay of motion and sound production by active agents (i.e., dancers) in the field. Agreeing that human entrainment should be studied on multiple levels, we suggest that entrainment between the dancers in Duo is elastic in time and propose how to test this hypothesis empirically. We do not claim that our proposed model of elasticity is applicable to all forms of human entrainment nor to all examples of entrainment in dance. Rather, we suggest studying higher order phase correction (the stabilizing tendency of entrainment) as a potential aspect to be incorporated into other models. PMID:25374522

  8. A survey of processes for producing hydrogen fuel from different sources for automotive-propulsion fuel cells

    SciTech Connect

    Brown, L.F.

    1996-03-01

    Seven common fuels are compared for their utility as hydrogen sources for proton-exchange-membrane fuel cells used in automotive propulsion. Methanol, natural gas, gasoline, diesel fuel, aviation jet fuel, ethanol, and hydrogen are the fuels considered. Except for the steam reforming of methanol and using pure hydrogen, all processes for generating hydrogen from these fuels require temperatures over 1000 K at some point. With the same two exceptions, all processes require water-gas shift reactors of significant size. All processes require low-sulfur or zero-sulfur fuels, and this may add cost to some of them. Fuels produced by steam reforming contain {approximately}70-80% hydrogen, those by partial oxidation {approximately}35-45%. The lower percentages may adversely affect cell performance. Theoretical input energies do not differ markedly among the various processes for generating hydrogen from organic-chemical fuels. Pure hydrogen has severe distribution and storage problems. As a result, the steam reforming of methanol is the leading candidate process for on-board generation of hydrogen for automotive propulsion. If methanol unavailability or a high price demands an alternative process, steam reforming appears preferable to partial oxidation for this purpose.

  9. Technical and regulatory review of the Rover nuclear fuel process for use on Fort St. Vrain fuel

    SciTech Connect

    Hertzler, T. )

    1993-02-01

    This report describes the results of an analysis for processing and final disposal of Fort St. Vrain (FSV) irradiated fuel in Rover-type equipment or technologies. This analysis includes an evaluation of the current Rover equipment status and the applicability of this technology in processing FSV fuel. The analyses are based on the physical characteristics of the FSV fuel and processing capabilities of the Rover equipment. Alternate FSV fuel disposal options are also considered including fuel-rod removal from the block, disposal of the empty block, or disposal of the entire fuel-containing block. The results of these analyses document that the current Rover hardware is not operable for any purpose, and any effort to restart this hardware will require extensive modifications and re-evaluation. However, various aspects of the Rover technology, such as the successful fluid-bed burner design, can be applied with modification to FSV fuel processing. The current regulatory climate and technical knowledge are not adequately defined to allow a complete analysis and conclusion with respect to the disposal of intact fuel blocks with or without the fuel rods removed. The primary unknowns include the various aspects of fuel-rod removal from the block, concentration of radionuclides remaining in the graphite block after rod removal, and acceptability of carbon in the form of graphite in a high level waste repository.

  10. Temperature compensation and entrainment in circadian rhythms

    NASA Astrophysics Data System (ADS)

    Bodenstein, C.; Heiland, I.; Schuster, S.

    2012-06-01

    To anticipate daily variations in the environment and coordinate biological activities into a daily cycle many organisms possess a circadian clock. In the absence of external time cues the circadian rhythm persists with a period of approximately 24 h. The clock phase can be shifted by single pulses of light, darkness, chemicals, or temperature and this allows entrainment of the clock to exactly 24 h by cycles of these zeitgebers. On the other hand, the period of the circadian rhythm is kept relatively constant within a physiological range of constant temperatures, which means that the oscillator is temperature compensated. The mechanisms behind temperature compensation and temperature entrainment are not fully understood, neither biochemically nor mathematically. Here, we theoretically investigate the interplay of temperature compensation and entrainment in general oscillatory systems. We first give an analytical treatment for small temperature shifts and derive that every temperature-compensated oscillator is entrainable to external small-amplitude temperature cycles. Temperature compensation ensures that this entrainment region is always centered at the endogenous period regardless of possible seasonal temperature differences. Moreover, for small temperature cycles the entrainment region of the oscillator is potentially larger for rectangular pulses. For large temperature shifts we numerically analyze different circadian clock models proposed in the literature with respect to these properties. We observe that for such large temperature shifts sinusoidal or gradual temperature cycles allow a larger entrainment region than rectangular cycles.

  11. Entrained neural oscillations in multiple frequency bands comodulate behavior

    PubMed Central

    Henry, Molly J.; Herrmann, Björn

    2014-01-01

    Our sensory environment is teeming with complex rhythmic structure, to which neural oscillations can become synchronized. Neural synchronization to environmental rhythms (entrainment) is hypothesized to shape human perception, as rhythmic structure acts to temporally organize cortical excitability. In the current human electroencephalography study, we investigated how behavior is influenced by neural oscillatory dynamics when the rhythmic fluctuations in the sensory environment take on a naturalistic degree of complexity. Listeners detected near-threshold gaps in auditory stimuli that were simultaneously modulated in frequency (frequency modulation, 3.1 Hz) and amplitude (amplitude modulation, 5.075 Hz); modulation rates and types were chosen to mimic the complex rhythmic structure of natural speech. Neural oscillations were entrained by both the frequency modulation and amplitude modulation in the stimulation. Critically, listeners’ target-detection accuracy depended on the specific phase–phase relationship between entrained neural oscillations in both the 3.1-Hz and 5.075-Hz frequency bands, with the best performance occurring when the respective troughs in both neural oscillations coincided. Neural-phase effects were specific to the frequency bands entrained by the rhythmic stimulation. Moreover, the degree of behavioral comodulation by neural phase in both frequency bands exceeded the degree of behavioral modulation by either frequency band alone. Our results elucidate how fluctuating excitability, within and across multiple entrained frequency bands, shapes the effective neural processing of environmental stimuli. More generally, the frequency-specific nature of behavioral comodulation effects suggests that environmental rhythms act to reduce the complexity of high-dimensional neural states. PMID:25267634

  12. Modified mass action law-based model to correlate the solubility of solids and liquids in entrained supercritical carbon dioxide.

    PubMed

    González, J C; Vieytes, M R; Botana, A M; Vieites, J M; Botana, L M

    2001-02-23

    The solubility of solids and liquids in supercritical CO2 with added entrainers was modeled with a modified version of the equation of Chrastil to include the effect of entrainers. By considering the formation of the solute-entrainer-solvent complexes an equation is obtained which predicts an exponential increase of solubility with fluid density and/or entrainer concentration. The correlating model was tested by non-linear regression through a computerized iterative process for several systems where an entrainer was present. Four experimental parameters are easily regressed from experimental data, hence the corresponding properties of components such as chemical potentials or critical parameters are not needed. Instead of its simplicity, this thermodynamical model provided a good correlation of the solubility enhancement in the presence of entrainer effect. PMID:11263564

  13. Entrainment ranges of forced phase oscillators.

    PubMed

    Previte, Joseph P; Sheils, Natalie; Hoffman, Kathleen A; Kiemel, Tim; Tytell, Eric D

    2011-04-01

    In the vertebrate spinal cord, a neural circuit called the central pattern generator produces the basic locomotory rhythm. Short and long distance intersegmental connections serve to maintain coordination along the length of the body. As a way of examining the influence of such connections, we consider a model of a chain of coupled phase oscillators in which one oscillator receives a periodic forcing stimulus. For a certain range of forcing frequencies, the chain will match the stimulus frequency, a phenomenon called entrainment. Motivated by recent experiments in lampreys, we derive analytical expressions for the range of forcing frequencies that entrain the chain, and how that range depends on the forcing location. For short intersegmental connections, in which an oscillator is connected only to its nearest neighbors, we describe two ways in which entrainment is lost: internally, in which oscillators within the chain no longer oscillate at the same frequency; and externally, in which the the chain no longer has the same frequency as the forcing. By analyzing chains in which every oscillator is connected to every other oscillator (i.e., all-to-all connections), we show that the presence of connections with lengths greater than one do not necessarily change the entrainment ranges based on the nearest-neighbor model. We derive a criterion for the ratio of connection strengths under which the connections of length greater than one do not change the entrainment ranges produced in the nearest-neighbor model, provided entrainment is lost externally. However, when this criterion holds, the range of entrained frequencies is a monotonic function of forcing location, unlike experimental results, in which entrainment ranges are larger near the middle of the chain than at the ends. Numerically, we show that similar non-monotonic entrainment ranges are possible if the ratio criterion does not hold, suggesting that in the lamprey central pattern generator, intersegmental

  14. Neurobiological foundations of neurologic music therapy: rhythmic entrainment and the motor system

    PubMed Central

    Thaut, Michael H.; McIntosh, Gerald C.; Hoemberg, Volker

    2015-01-01

    Entrainment is defined by a temporal locking process in which one system’s motion or signal frequency entrains the frequency of another system. This process is a universal phenomenon that can be observed in physical (e.g., pendulum clocks) and biological systems (e.g., fire flies). However, entrainment can also be observed between human sensory and motor systems. The function of rhythmic entrainment in rehabilitative training and learning was established for the first time by Thaut and colleagues in several research studies in the early 1990s. It was shown that the inherent periodicity of auditory rhythmic patterns could entrain movement patterns in patients with movement disorders (see for a review: Thaut et al., 1999). Physiological, kinematic, and behavioral movement analysis showed very quickly that entrainment cues not only changed the timing of movement but also improved spatial and force parameters. Mathematical models have shown that anticipatory rhythmic templates as critical time constraints can result in the complete specification of the dynamics of a movement over the entire movement cycle, thereby optimizing motor planning and execution. Furthermore, temporal rhythmic entrainment has been successfully extended into applications in cognitive rehabilitation and speech and language rehabilitation, and thus become one of the major neurological mechanisms linking music and rhythm to brain rehabilitation. These findings provided a scientific basis for the development of neurologic music therapy. PMID:25774137

  15. Neurobiological foundations of neurologic music therapy: rhythmic entrainment and the motor system.

    PubMed

    Thaut, Michael H; McIntosh, Gerald C; Hoemberg, Volker

    2014-01-01

    Entrainment is defined by a temporal locking process in which one system's motion or signal frequency entrains the frequency of another system. This process is a universal phenomenon that can be observed in physical (e.g., pendulum clocks) and biological systems (e.g., fire flies). However, entrainment can also be observed between human sensory and motor systems. The function of rhythmic entrainment in rehabilitative training and learning was established for the first time by Thaut and colleagues in several research studies in the early 1990s. It was shown that the inherent periodicity of auditory rhythmic patterns could entrain movement patterns in patients with movement disorders (see for a review: Thaut et al., 1999). Physiological, kinematic, and behavioral movement analysis showed very quickly that entrainment cues not only changed the timing of movement but also improved spatial and force parameters. Mathematical models have shown that anticipatory rhythmic templates as critical time constraints can result in the complete specification of the dynamics of a movement over the entire movement cycle, thereby optimizing motor planning and execution. Furthermore, temporal rhythmic entrainment has been successfully extended into applications in cognitive rehabilitation and speech and language rehabilitation, and thus become one of the major neurological mechanisms linking music and rhythm to brain rehabilitation. These findings provided a scientific basis for the development of neurologic music therapy. PMID:25774137

  16. Thermal measurements and computational simulations of three-phase (CeO2-MgAl2O4-CeMgAl11O19) and four-phase (3Y-TZP-Al2O3-MgAl2O4-LaPO4) composites as surrogate inert matrix nuclear fuel

    NASA Astrophysics Data System (ADS)

    Angle, Jesse P.; Nelson, Andrew T.; Men, Danju; Mecartney, Martha L.

    2014-11-01

    This study investigates the temperature dependent thermal conductivity of multiphase ceramic composites for simulated inert matrix nuclear fuel. Fine grained composites were made of CeO2-MgAl2O4-CeMgAl11O19 or 3Y-TZP-Al2O3-MgAl2O4-LaPO4. CeO2 and 3Y-TZP are used as UO2 surrogates due to their similar structures and low thermal conductivities. Laser flash analysis from room temperature to 1273 K (1000 °C) was used to determine the temperature dependent thermal conductivity. A computational approach using Object Oriented Finite Element Analysis Version 2 (OOF2) was employed to simulate the composite thermal conductivity based on the microstructure. Observed discrepancies between experimental and simulated thermal conductivities at low temperature may be due to Kapitza resistance; however, there is less than 3% deviation between models and experiments above 673 K (400 °C) for both compositions. When the surrogate phase was replaced with UO2 in the computational model for the four-phase composite, a 12-16% increase in thermal conductivity resulted compared to single phase UO2, in the range of 673-1273 K (400-1000 °C). This computational approach may be potentially viable for the high-throughput evaluation of composite systems and the strategic selection of inert phases without extensive sample fabrication during the initial development stages of composite nuclear fuel design.

  17. Plate-Based Fuel Processing System Final Report

    SciTech Connect

    Carlos Faz; Helen Liu; Jacques Nicole; David Yee

    2005-12-22

    On-board reforming of liquid fuels into hydrogen is an enabling technology that could accelerate consumer usage of fuel cell powered vehicles. The technology would leverage the convenience of the existing gasoline fueling infrastructure while taking advantage of the fuel cell efficiency and low emissions. Commercial acceptance of on-board reforming faces several obstacles that include: (1) startup time, (2) transient response, and (3) system complexity (size, weight and cost). These obstacles are being addressed in a variety of projects through development, integration and optimization of existing fuel processing system designs. In this project, CESI investigated steam reforming (SR), water-gas-shift (WGS) and preferential oxidation (PrOx) catalysts while developing plate reactor designs and hardware where the catalytic function is integrated into a primary surface heat exchanger. The plate reactor approach has several advantages. The separation of the reforming and combustion streams permits the reforming reaction to be conducted at a higher pressure than the combustion reaction, thereby avoiding costly gas compression for combustion. The separation of the two streams also prevents the dilution of the reformate stream by the combustion air. The advantages of the plate reactor are not limited to steam reforming applications. In a WGS or PrOx reaction, the non-catalytic side of the plate would act as a heat exchanger to remove the heat generated by the exothermic WGS or PrOx reactions. This would maintain the catalyst under nearly isothermal conditions whereby the catalyst would operate at its optimal temperature. Furthermore, the plate design approach results in a low pressure drop, rapid transient capable and attrition-resistant reactor. These qualities are valued in any application, be it on-board or stationary fuel processing, since they reduce parasitic losses, increase over-all system efficiency and help perpetuate catalyst durability. In this program, CESI

  18. Fuel quality/processing study. Volume 2: Appendix. Task 1 literature survey

    NASA Technical Reports Server (NTRS)

    Ohara, J. B.; Bela, A.; Jentz, N. E.; Klumpe, H. W.; Kessler, H. E.; Kotzot, H. T.; Loran, B. L.

    1981-01-01

    The results of a literature survey of fuel processing and fuel quality are given. Liquid synfuels produced from coal and oil shale are discussed. Gas turbine fuel property specifications are discussed. On-site fuel pretreatment and emissions from stationary gas turbines are discussed. Numerous data tables and abstracts are given.

  19. Conversion of microalgae to jet fuel: process design and simulation.

    PubMed

    Wang, Hui-Yuan; Bluck, David; Van Wie, Bernard J

    2014-09-01

    Microalgae's aquatic, non-edible, highly genetically modifiable nature and fast growth rate are considered ideal for biomass conversion to liquid fuels providing promise for future shortages in fossil fuels and for reducing greenhouse gas and pollutant emissions from combustion. We demonstrate adaptability of PRO/II software by simulating a microalgae photo-bio-reactor and thermolysis with fixed conversion isothermal reactors adding a heat exchanger for thermolysis. We model a cooling tower and gas floatation with zero-duty flash drums adding solids removal for floatation. Properties data are from PRO/II's thermodynamic data manager. Hydrotreating is analyzed within PRO/II's case study option, made subject to Jet B fuel constraints, and we determine an optimal 6.8% bioleum bypass ratio, 230°C hydrotreater temperature, and 20:1 bottoms to overhead distillation ratio. Process economic feasibility occurs if cheap CO2, H2O and nutrient resources are available, along with solar energy and energy from byproduct combustion, and hydrotreater H2 from product reforming. PMID:24997379

  20. Effect of firing temperature on the microstructure and performance of PrBaCo 2O 5+ δ cathodes on Sm 0.2Ce 0.8O 1.9 electrolytes fabricated by spray deposition-firing processes

    NASA Astrophysics Data System (ADS)

    Chen, Dengjie; Ran, Ran; Shao, Zongping

    The effect of firing temperature on the microstructure and performance of PrBaCo 2O 5+ δ cathodes on Sm 0.2Ce 0.8O 1.9 electrolytes fabricated by spray deposition-firing processes is systematically studied by various characterization techniques. The grain size, porosity and particle connection of the electrode as well as the physical contact between the PrBaCo 2O 5+ δ and Sm 0.2Ce 0.8O 1.9 layers are influenced differently by the firing temperature. The area specific resistances (ASRs) of the various PrBaCo 2O 5+ δ cathodes are measured by electrochemical impedance spectroscopy in both symmetrical two-electrode and three-electrode configurations. The lowest ASR and cathode overpotential are achieved at a firing temperature of 1000 °C. Two main oxygen reduction reaction processes are proposed according to the oxygen partial pressure dependence of the electrode ASR. The rate-determining step is transmitted from a charge-transfer process at low firing temperatures to a non-charge-transfer process at high firing temperatures. A fuel cell with the PrBaCo 2O 5+ δ cathode fired at an optimal temperature of 1000 °C delivers the attractive peak power density of 835 mW cm -2 at 650 °C, while this density is much lower for other firing temperatures. This result suggests the firing temperature of PrBaCo 2O 5+ δ electrodes should be carefully optimized for practical applications.

  1. Microbial fuel cell treatment of ethanol fermentation process water

    SciTech Connect

    Borole, Abhijeet P.

    2012-06-05

    The present invention relates to a method for removing inhibitor compounds from a cellulosic biomass-to-ethanol process which includes a pretreatment step of raw cellulosic biomass material and the production of fermentation process water after production and removal of ethanol from a fermentation step, the method comprising contacting said fermentation process water with an anode of a microbial fuel cell, said anode containing microbes thereon which oxidatively degrade one or more of said inhibitor compounds while producing electrical energy or hydrogen from said oxidative degradation, and wherein said anode is in electrical communication with a cathode, and a porous material (such as a porous or cation-permeable membrane) separates said anode and cathode.

  2. PROCESS OF MAKING SHAPED FUEL FOR NUCLEAR REACTORS

    DOEpatents

    O'Leary, W.J.; Fisher, E.A.

    1964-02-11

    A process for making uranium dioxide fuel of great strength, density, and thermal conductivity by mixing it with 0.1 to 1% of a densifier oxide (tin, aluminum, zirconium, ferric, zinc, chromium, molybdenum, titanium, or niobium oxide) and with a plasticizer (0.5 to 3% of bentonite and 0.05 to 2% of methylcellulose, propylene glycol alginate, or ammonium alginate), compacting the mixture obtained, and sintering the bodies in an atmosphere of carbon monoxide or carbon dioxide, with or without hydrogen, or of a nitrogen-hydrogen mixture is described. (AEC)

  3. Process for recovery of palladium from nuclear fuel reprocessing wastes

    DOEpatents

    Campbell, David O.; Buxton, Samuel R.

    1981-01-01

    Palladium is selectively removed from spent nuclear fuel reprocessing waste by adding sugar to a strong nitric acid solution of the waste to partially denitrate the solution and cause formation of an insoluble palladium compound. The process includes the steps of: (a) adjusting the nitric acid content of the starting solution to about 10 M, (b) adding 50% sucrose solution in an amount sufficient to effect the precipitation of the palladium compound, (c) heating the solution at reflux temperature until precipitation is complete, and (d) centrifuging the solution to separate the precipitated palladium compound from the supernatant liquid.

  4. Automated catalyst processing for cloud electrode fabrication for fuel cells

    DOEpatents

    Goller, Glen J.; Breault, Richard D.

    1980-01-01

    A process for making dry carbon/polytetrafluoroethylene floc material, particularly useful in the manufacture of fuel cell electrodes, comprises of the steps of floccing a co-suspension of carbon particles and polytetrafluoroethylene particles, filtering excess liquids from the co-suspension, molding pellet shapes from the remaining wet floc solids without using significant pressure during the molding, drying the wet floc pellet shapes within the mold at temperatures no greater than about 150.degree. F., and removing the dry pellets from the mold.

  5. PROCESS OF MAKING A NEUTRONIC REACTOR FUEL ELEMENT COMPOSITION

    DOEpatents

    Alter, H.W.; Davidson, J.K.; Miller, R.S.; Mewherter, J.L.

    1959-01-13

    A process is presented for making a ceramic-like material suitable for use as a nuclear fuel. The material consists of a solid solution of plutonium dioxide in uranium dioxide and is produced from a uranyl nitrate -plutonium nitrate solution containing uraniunm and plutonium in the desired ratio. The uranium and plutonium are first precipitated from the solution by addition of NH/ sub 4/OH and the dried precipitate is then calcined at 600 C in a hydrogen atmosphere to yield the desired solid solution of PuO/sub 2/ in UO/sub 2/.

  6. Process for recovery of palladium from nuclear fuel reprocessing wastes

    DOEpatents

    Campbell, D.O.; Buxton, S.R.

    1980-06-16

    Palladium is selectively removed from spent nuclear fuel reprocessing waste by adding sugar to a strong nitric acid solution of the waste to partially denitrate the solution and cause formation of an insoluble palladium compound. The process includes the steps of: (a) adjusting the nitric acid content of the starting solution to about 10 M; (b) adding 50% sucrose solution in an amount sufficient to effect the precipitation of the palladium compound; (c) heating the solution at reflux temperature until precipitation is complete; and (d) centrifuging the solution to separate the precipitated palladium compound from the supernatant liquid.

  7. Laboratory experiments on stability and entrainment of oceanic stratocumulus. Part 1: Instability experiment

    NASA Technical Reports Server (NTRS)

    Shy, Shenqyang S.

    1990-01-01

    The existence and persistence of marine stratocumulus play a significant role in the overall energy budget of the earth. Their stability and entrainment process are important in global climate studies, as well as for local weather forecasting. The purposes of the experimental simulations are to study this process and to address this paradox. The effects of buoyancy reversal is investigated, followed by two types of experiments. An instability experiment involves the behavior of a fully turbulent wake near the inversion generated by a sliding plate. Due to buoyancy reversal, the heavy, mixed fluid starts to sink, turning the potential energy created by the mixing process into kinetic energy, thereby increasing the entrainment rate. An entrainment experiment, using a vertically oscillating grid driven by a controllable speed motor, produces many eddy-induced entrainments at a surface region on scales much less than the depth of the layer.

  8. Low temperature co-sintering of Sr2Fe1.5Mo0.5O6-δ-Gd0.1Ce0.9O2-δ anode-supported solid oxide fuel cells with Li2O-Gd0.1Ce0.9O2-δ electrolyte

    NASA Astrophysics Data System (ADS)

    Yang, Zhibin; Yang, Yanru; Chen, Yu; Liu, Yahui; Zhu, Tenglong; Han, Minfang; Chen, Fanglin

    2015-11-01

    Sr2Fe1.5Mo0.5O6-δ-Gd0.1Ce0.9O1.95(SFM-GDC) ceramic anode-supported solid oxide fuel cell with GDC crack-free electrolyte film (∼80 μm) has been fabricated by co-pressing and co-sintering at temperature as low as 1150 °C for 5 h by introducing 2.5 mol% Li2O as sintering-aid. The peak power density of such cells with Ba0.9Co0.7Fe0.2Nb0.1O3-δ (BCFN) cathode can reach 200 mW cm-2 at 700 °C when using H2 as fuel and ambient air as oxidant. In addition, the anode shows an excellent sulfur tolerance when using H2 with 50 ppm H2S as fuel.

  9. Flow Dynamics and Sediment Entrainment in Natural Turbidity Currents Inferred from Numerical Modeling

    NASA Astrophysics Data System (ADS)

    Traer, M. M.; Hilley, G. E.; Fildani, A.

    2009-12-01

    Submarine turbidity currents derive their momentum from gravity acting upon the density contrast between sediment-laden and clear water, and so unlike fluvial systems, the dynamics of such flows are inextricably linked to the rates at which they deposit and entrain sediment. We have analyzed the sensitivity of the growth and maintenance of turbidity currents to sediment entrainment and deposition using the layer-averaged equations of conservation of fluid and sediment mass, and conservation of momentum and turbulent kinetic energy. Our model results show that the dynamics of turbidity currents are extremely sensitive to the functional form and empirical constants of the relationship between sediment entrainment and friction velocity. Data on the relationship between sediment entrainment and friction velocity for submarine density flows are few and as a result, entrainment formulations are populated with data from sub-aerial flows not driven by the density contrast between clear and turbid water. If we entertain the possibility that sediment entrainment in sub-aerial rivers is different than in dense underflows, flow parameters such as velocity, height, and concentration were found nearly impossible to predict beyond a few hundred meters based on the limited laboratory data available that constrain the sediment entrainment process in turbidity currents. The sensitivity of flow dynamics to the functional relationship between friction velocity and sediment entrainment indicates that independent calibration of a sediment entrainment law in the submarine environment is necessary to realistically predict the dynamics of these flows and the resulting patterns of erosion and deposition. To calibrate such a relationship, we have developed an inverse methodology that utilizes existing submarine channel morphology as a means of constraining the sediment entrainment function parameters. We use a Bayesian Metropolis-Hastings sampler to determine the sediment entrainment

  10. Sintering Studies of Ga-Doped CeO{sub 2} (Ga-Doped PuO{sub 2} Surrogate) for Mixed Oxide Nuclear Fuel

    SciTech Connect

    Haertling, C.; Huling, J.; Park, Y.S.

    1999-04-25

    Sintering studies of CeO{sub 2} and CeO{sub 2} + 2 wt. % Ga{sub 2}O{sub 3} were completed. Firing temperatures studied were 1250-1650 C with 2 to 4 hour firing soak times in air. Powders fabricated by three methods (as-received, attrition-mill and nitrite-derived) were studied. Attrition-milled CeO{sub 2} improved densities as compared with as-received CeO{sub 2}. Attrition-milled CeO{sub 2} with 2 wt.% Ga{sub 2}O{sub 3} showed decreased densities with increasing temperatures. As-received CeO{sub 2} with 2 wt.% Ga{sub 2}O{sub 3} showed a opposite trend, increasing in density with increased firing temperature. Two pellet preparation methods were studied, a one-step-press method and a two-step-press method. The two-step-press method showed greater densities at lower firing temperatures and times as compared with the one-step-press method, however for CeO{sub 2} + 2 wt.% Ga{sub 2}O{sub 3}, the two methods gave equivalent results at 1650 C, 6 hr. firing conditions.